Reports.HallEffectDirectionDetectionSensor History

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Ceramic magnet \\
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Ceramic magnet :
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Rare earth magnet :
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http://www.radioshack.com/product/index.jsp?productId=2102641&cp=&kw=magnets&parentPage=search
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[[http://www.radioshack.com/product/index.jsp?productId=2102641&cp=&kw=magnets&parentPage=search | Radioshack link]]
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http://www.radioshack.com/product/index.jsp?productId=2102642&cp=&pg=1&kw=magnets&parentPage=search
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[[http://www.radioshack.com/product/index.jsp?productId=2102642&cp=&pg=1&kw=magnets&parentPage=search | Radioshack link]]
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Video for the rare earth magnet:

http:
//itp.nyu.edu/~jg1646/sensors/videos/DirectionRare.avi
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[[http://itp.nyu.edu/~jg1646/sensors/videos/DirectionRare.avi | Video for the rare earth magnet]]

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Video for the ceramic ring magnet:

http:
//itp.nyu.edu/~jg1646/sensors/videos/E1Ceramic.avi


Video for the rare earth
magnet:

http:
//itp.nyu.edu/~jg1646/sensors/videos/E1Rare.avi
to:
[[http://itp.nyu.edu/~jg1646/sensors/videos/E1Ceramic.avi | Video for the ceramic ring magnet]]



[[http
://itp.nyu.edu/~jg1646/sensors/videos/E1Rare.avi | Video for the rare earth magnet]]
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http://itp.nyu.edu/~jg1646/sensors/videos/042506_020.avi
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[[http://itp.nyu.edu/~jg1646/sensors/videos/042506_020.avi | PedalPlay in Action]]
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Video for the ceramic ring magnet:

http:
//itp.nyu.edu/~jg1646/sensors/videos/DirectionCeramic.avi
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[[http://itp.nyu.edu/~jg1646/sensors/videos/DirectionCeramic.avi | Video for the ceramic ring magnet]]
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http://itp.nyu.edu/~jg1646/sensors/videos/042506_020.avi
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://itp.nyu.edu/~jg1646/sensors/box_close.jpg
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http:
//itp.nyu.edu/~jg1646/sensors/box_closed.jpg
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Attach:box_close.jpg
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There were two major hurdles I encountered before getting solid data from my sensor. The first was getting the sensor firmly attached so that when the magnet passed by on the wheel the two would be a set distance apart. Here is a picture of the encasement I built so that I could mount the sensor on the bike:
to:
There were two major hurdles I encountered before getting solid data from my sensor. The first was getting the sensor firmly attached so that when the magnet passed by on the wheel the two would be a set distance apart (about 1/8"). Here is a picture of the encasement I built so that I could mount the sensor on the bike:
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With the RJ-ll connector on the cable and the matching receptor on my microcontroller box it will be very easy for the Occupation Therapists at the school I'm working with to attach the sensor cable. The other half - sending data to the computer and powering the microcontroller - is accomplished nicely by a USB cable. The chip being used here is the PIC18F2550. Thanks to Amit Pitaru for introducing me to the chip and getting me up and running with it.
to:
With the RJ-ll connector on the cable and the matching receptor on my microcontroller box it will be very easy for the Occupation Therapists at the school I'm working with to attach the sensor cable. The other half - sending data to the computer and powering the microcontroller - is accomplished nicely by a USB cable. The microcontoller receives about 5V from the computer which is perfect for the chip and enough for the sensor (which needs more than 4.5V). The chip being used here is the PIC18F2550. Thanks to Amit Pitaru for introducing me to the chip and getting me up and running with it.
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The second hurdle was figuring out I needed pull-up resistors. Let me repeat that because it's very important: '''PULL-UP RESISTORS'''. My numbers were wonky (yes, that's the technical term) and I was trying various values of pull-down resistors. Here is the FAQ sheet on Allegro that proved helpful: [[http://www.allegromicro.com/faq/hedfaq1.htm | FAQs : Digital Hall-Effect Sensors ]]
to:
The second hurdle was figuring out I needed pull-up resistors. Let me repeat that because it's very important: '''PULL-UP RESISTORS'''. My numbers were wonky (yes, that's the technical term) and I was trying various values of pull-down resistors. Here is the FAQ sheet on Allegro that proved helpful: [[http://www.allegromicro.com/faq/hedfaq1.htm | FAQs : Digital Hall-Effect Sensors ]]

And finally, a brief video of the project working.

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Here it is finally mounted on the bike. You can see the magnet near the bottom that slides by the sensor when pedaling begins.

http://itp.nyu.edu/~jg1646/sensors/sensor_attached.jpg
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http://itp.nyu.edu/~jg1646/sensors/sensor_wire.jpg



The rigidness of the bike will probably make attachment easier, so now
it's a matter of getting the ok to bring the bike school.
The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed
.
to:
http://itp.nyu.edu/~jg1646/sensors/box_open.jpg

http://itp.nyu.edu/~jg1646/sensors/box_close.jpg

The second hurdle was figuring out I needed pull-up resistors. Let me repeat that because
it's very important: '''PULL-UP RESISTORS'''. My numbers were wonky (yes, that's the technical term) and I was trying various values of pull-down resistors. Here is the FAQ sheet on Allegro that proved helpful: [[http://www.allegromicro.com/faq/hedfaq1.htm | FAQs : Digital Hall-Effect Sensors ]]
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I chose this sensor to use it as a tachomter for a stationary bicycle. The direction sensing is important to me because I need to know if the users (students at a school for children with autism) pedal backwards and change the output accordingly.
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I chose this sensor to use as a tachomter for a stationary bicycle in my project PedalPlay. The basic project idea is to motivate students at a school for children with autism to use the bike in their gym. The method for accomplishing this is connecting the bike to the computer they have in the gym and controlling the playback volume and brightness of a video by the rate the student pedals. The sensor sends the data from the bike to the microcontroller which calculates the range the student is pedaling and in turn sends this to a Max/MSP/Jitter patch that controls the video. The direction sensing is important to me because I need to know if the users pedal backwards and then change the output accordingly.
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http://itp.nyu.edu/~jg1646/sensors/sensor_close.jpg

As you can see better from this next picture, I have the sensor wired to a shielded cable (normally used for phones) that has six wires and ending in an RJ-11 connector. It worked very nicely for my 5 pin sensor.

http://itp.nyu.edu/~jg1646/sensors/sensor_wire.jpg

With the RJ-ll connector on the cable and the matching receptor on my microcontroller box it will be very easy for the Occupation Therapists at the school I'm working with to attach the sensor cable. The other half - sending data to the computer and powering the microcontroller - is accomplished nicely by a USB cable. The chip being used here is the PIC18F2550. Thanks to Amit Pitaru for introducing me to the chip and getting me up and running with it.

http://itp.nyu.edu/~jg1646/sensors/sensor_wire.jpg
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The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed.
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The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed.
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!!!!Plans
Part of the problem is getting the
sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but it should succeed. The rigidness of the bike will probably make attachment easier, so now it's a matter of getting the ok to bring the bike school.
to:
!!!!My Application - PedalPlay
I chose this
sensor to use it as a tachomter for a stationary bicycle. The direction sensing is important to me because I need to know if the users (students at a school for children with autism) pedal backwards and change the output accordingly.

There were two major hurdles I encountered before getting solid data from my sensor. The first was getting the sensor firmly attached so that when the magnet passed by on
the wheel the two would be a set distance apart. Here is a picture of the encasement I built so that I could mount the sensor on the bike:




The rigidness of the bike will probably make attachment easier, so now it's a matter of getting the ok to bring the bike school.
The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed.
Changed line 205 from:
Part of the problem is getting the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but it should succeed. The rigidness of the bike will probably make attachment easier, so now it's a matter of getting the ok to bring the bike school.
to:
Part of the problem is getting the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but it should succeed. The rigidness of the bike will probably make attachment easier, so now it's a matter of getting the ok to bring the bike school.
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Part of the problem is getting the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but the rigidness of the bike will probably make attachment easier.
to:
Part of the problem is getting the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but it should succeed. The rigidness of the bike will probably make attachment easier, so now it's a matter of getting the ok to bring the bike school.
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!!!!!Direction Pin
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!!!!!Direction Pin (increments of 5mV)
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!!!!!E1Output Pin
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!!!!!E1Output Pin (increments of 50mV)
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Part of the problem is having the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but do the job nonetheless.
to:
Part of the problem is getting the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but the rigidness of the bike will probably make attachment easier.
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Part of the problem is having the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but do the job nonetheless.
to:
Part of the problem is having the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but do the job nonetheless.
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!!!!!Testing
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!!!!Testing
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!!!!!Plans
Part of the problem is having the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but do the job nonetheless.
to:
\\
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!!!!Plans
Part of the problem is having the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but do the job nonetheless.
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Part of the problem is having the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but do the job nonetheless.
to:
Part of the problem is having the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but do the job nonetheless.
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Part of the problem is having the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but do the job nonetheless.
to:
Part of the problem is having the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but do the job nonetheless.
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\\
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\\
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Part of the problem is having the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but do the job nonetheless.
to:
Part of the problem is having the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but do the job nonetheless.
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Ceramic magnet
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Ceramic magnet \\
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Rare earth magnet
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Rare earth magnet \\
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Part of the problem is having the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but do the job nonetheless.
to:
Part of the problem is having the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but do the job nonetheless.
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!!!!Quadrature relationship
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Part of the problem is having the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but do the job nonetheless.
to:
Part of the problem is having the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but do the job nonetheless.
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!!!!!Magnets
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!!!!Magnets
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Part of the problem is having the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but do the job nonetheless.
to:
Part of the problem is having the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but do the job nonetheless.
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!!!!!Plans
Part of the problem is having the sensor and magnet firmly attached at set distances apart. The oscilloscope test has assured me that the sensor is working, but much fine tuning is needed. For my ultimate purpose of using it as a tachomter for a stationary bicycle this sensor might be overkill, but do the job nonetheless.
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[[Attach:magnets.jpg]]
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http://itp.nyu.edu/~jg1646/sensors/magnets.jpg
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http://itp.nyu.edu/~jg1646/sensors/ringmagnet.jpg
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http://itp.nyu.edu/~jg1646/sensors/raremagnet.jpg
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[[Attach: quadrature.jpg ]]
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http://itp.nyu.edu/~jg1646/sensors/quadrature.jpg
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[[Attach: board.jpg]]
[[Attach
: board2.jpg]]
to:
http://itp.nyu.edu/~jg1646/sensors/board.jpg
http://itp.nyu.edu/~jg1646/sensors/board2.jpg
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!!Intended Applications
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!!!!!Intended Applications
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Like other hall effect sensors, as mentioned in John Schimmel's datasheet, this one also detects a magnetic field and acts as a switch (on/off state). However, it also has the unique capability of being able to determine the direction that the magnet (Allegro recommends a ring one)is rotating (as you might have guessed by the name). This built in capability is what interested me in the sensor. Although you could accomplish the same goal yourself by using two hall sensors and calculate the direction by which sensor passes you first, Allegro Microsystems has already done the job for you in a very precise way.
to:
Like other hall effect sensors, as mentioned in John Schimmel's datasheet, this one also detects a magnetic field and acts as a switch (on/off state). However, it also has the unique capability of being able to determine the direction that the magnet (Allegro recommends a high density ring magnet)is rotating (as you might have guessed by the name). This built in capability is what interested me in the sensor. Although you could accomplish the same goal yourself by using two hall sensors and calculate the direction by which sensor passes you first, Allegro Microsystems has already done the job for you in a very precise way.
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!!!!Intended Applications
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!!Intended Applications
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<table border='0' cellpadding='0' align="center">
<!-- begin video window
... -->
<tr>
<td><object classid='clsid:02BF25D5-8C17-4B23-BC80-D3488ABDDC6B' width="400"
height="265" codebase='http://www.apple.com/qtactivex/qtplugin.cab'>
<param name='src' value="http://itp.nyu.edu/~jg1646/sensors/videos/DirectionCeramic.
avi" />
<param name='autoplay' value="false" />
<param name='controller' value="true" />
<param name='loop' value="false" />
<embed src="DirectionCeramic.avi" width="320" height="240" autoplay="false"
controller="true" loop="False" pluginspage='http://www.apple.com/quicktime/download/'> </embed>
</object>
</td>
</tr>
<!-- ...end embedded QuickTime file -->
</table>



DirectionCeramic.avi
to:
http://itp.nyu.edu/~jg1646/sensors/videos/DirectionCeramic.avi
\\
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DirectionRare.avi
to:
http://itp.nyu.edu/~jg1646/sensors/videos/DirectionRare.avi
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E1Ceramic.avi
to:
http://itp.nyu.edu/~jg1646/sensors/videos/E1Ceramic.avi
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E1Rare.avi
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http://itp.nyu.edu/~jg1646/sensors/videos/E1Rare.avi
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<table border='0' cellpadding='0' align="center">
<!-- begin video window... -->
<tr>
<td><object classid='clsid:02BF25D5-8C17-4B23-BC80-D3488ABDDC6B' width="400"
height="265" codebase='http://www.apple.com/qtactivex/qtplugin.cab'>
<param name='src' value="http://itp.nyu.edu/~jg1646/sensors/videos/DirectionCeramic.avi" />
<param name='autoplay' value="false" />
<param name='controller' value="true" />
<param name='loop' value="false" />
<embed src="DirectionCeramic.avi" width="320" height="240" autoplay="false"
controller="true" loop="False" pluginspage='http://www.apple.com/quicktime/download/'> </embed>
</object>
</td>
</tr>
<!-- ...end embedded QuickTime file -->
</table>

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to:
Video for the ceramic ring magnet:
DirectionCeramic.avi
Video for the rare earth magnet:
DirectionRare.avi

!!!!!E1Output Pin
Video for the ceramic ring magnet:
E1Ceramic.avi
Video for the rare earth magnet:
E1Rare.avi
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!!!!!Testing
As mentioned before, there were initial problems getting any kind of readings from the sensor when supplying only 5V, so I bumped it up to 12V (max is 18V). Here are some pictures of the board:
[[Attach: board.jpg]]
[[Attach: board2.jpg]]

According to the timing diagram (shown earlier), the information from the pins is digital. I wanted to see what I was actually getting and first tried using a multimeter but soon switched to a digital oscilloscope. Below are my tests for both magnets.

!!!!!Direction Pin
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!!!Applications
to:
!!!!Intended Applications
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!!!!Sensor Locations
%center% http://itp.nyu.edu/~jg1646/sensors/locations.gif
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!!!Applications
Automotive (e.g. tachometer) \\
Industrial \\
Military \\
\\

This sensor is able to handle such a range of voltage (4.5V to 18V) because of a regulater that's built onto the chip. When I first wired the board for this sensor I tried using the power from the rest of the board (using a 5V regulator). I wasn't getting any readings from the sensor even though testing the wires with a multimeter indicated there were 5V going in. I believe that one of the features of the sensor, the under-voltage lockout, was preventing the sensor from turning on. Once I gave it 12V though I started getting readings.
I'm including some charts as well as diagrams from the datasheet even though I'm still mulling over the Magnetic Flux Density part. Basically it's a magnetic field, but this site goes into more detail: http://www.answers.com/topic/magnetic-field-density.
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!!!Applications
Automotive (e.g. tachometer) \\
Industrial \\
Military \\

This sensor is able to handle such a range of voltage (4.5V to 18V) because of a regulater that's built onto the chip. When I first wired the board for this sensor I tried using the power from the rest of the board (using a 5V regulator). I wasn't getting any readings from the sensor even though testing the wires with a multimeter indicated there were 5V going in. I believe that one of the features of the sensor, the under-voltage lockout, was preventing the sensor from turning on. Once I gave it 12V though I started getting readings.
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!!!!!Outputs
The device provides three saturated outputs: DIRECTION, E1 OUTPUT, and SPEED.
DIRECTION provides the direction output of the sensor and is defined as OFF (high) for the direction
E1 to E2 and ON (low) for the direction E2 to E1. SPEED provides an XOR'd output of the two sensors.
Because of internal delays, DIRECTION will always be updated before SPEED and is updated at every
transition of E1 OUTPUT and E2 OUTPUT (internal) allowing the use of up-down counters without the loss
of pulses.

!!!!!Power-On State
At power on, the logic circuitry is reset to provide an OFF (high) at DIRECTION and an
OFF (high) for E1 and E2 (internal) for magnetic fields less than BOP. This eliminates ambiguity when
the device is powered up and either sensor detects a field between BOP and BRP. If either sensor is subjected
to a field greater than BOP, the internal logic will set accordingly.
to:
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Automotive (e.g. tachometer)
Industrial
Military

The main components of this sensor are:
*Internal Direction-Decoding Circuitry
*Two Matched Hall Latches On A Single Substrate
*Temperature Stability
*4.5 V to 18 V Operation
*Electrically Defined Power-On State
*Under-Voltage Lockout
to:
Automotive (e.g. tachometer) \\
Industrial \\
Military \\
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Attach: quadrature.jpg


!!!!!Quadrature/Direction Detection
Internal logic circuitry provides outputs representing speed and direction of the magnetic field across the face of the package. For the direction signal to be appropriately updated, a quadrature relationship must be maintained
between the ring magnet pole width (pole being North or South), the sensor-to-sensor spacing, and, to a lesser extent, the magnetic switch points. For optimal design, the sensor should be actuated with a ring magnet pole width* two times
the sensor-to-sensor spacing. This will produce a sinusoidal magnetic field whose period (denoted as T)
is then four times the sensor-to-sensor spacing. A quadrature relationship can also be maintained for a
ring magnet that has a period that satisfies the relationship nT/4 = 1.5 mm, where n is any odd integer.
Therefore, ring magnets with pole-pair spacing equal to 6 mm (n = 1), 2 mm (n = 3), 1.2 mm (n = 5), etc.
are permitted.
to:
[[Attach: quadrature.jpg ]]
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The sensor comes with two aligned hall elements inside of it. And although Hall effect sensors are usually used in harsh environments (not affected by dirt like an optical sensor, and using the magnetic field means there's no need for contact), this one seems especially sturdy. There are two versions of the 3422, the

Applications
to:
The sensor comes with two aligned hall elements inside of it. And although Hall effect sensors are usually used in harsh environments (not affected by dirt like an optical sensor, and using the magnetic field means there's no need for contact), this one seems especially sturdy. There are two versions of the 3422, labeled by the suffix E- or L- that let you know the high end temperature range (both have a low end temperature range of -40&#730;C). As seen from the chart below the E- can withstand up to +85&#730;C, but the L- is rated to +150&#730;C (302&#730;F)! According to the datasheet the E- is used mostly in industry and the L- in military, though both in automotive.

(:table border=0 cellpadding=5 cellspacing=5 align=center:)
(:cell:)
|| border=1
||! MAXIMUM RATINGS !||
||Supply Voltage, VCC || 18 V ||
||Magnetic Flux Density, B || Unlimited ||
||Output OFF Voltage, VOUT || VCC ||
||Output Sink Current, IOUT || 30 mA ||
||Package Power Dissipation, PD || 500 mW ||
||Operating Temperature Range, TA ||||
||Suffix 'E-' || -40&#730;C to +85&#730;C ||
||Suffix 'L-' || -40&#730;C to +150&#730;C ||
|| Storage Temperature Range, TS || -65&#730;C to +170&#730;C ||

(:cell:) http://itp.nyu.edu/~jg1646/sensors/pinout.gif
(:tableend:)


!!!
Applications
Changed lines 28-29 from:
to:
Military
Changed lines 38-67 from:

This highly sensitive, temperature-stable, magnetic transducer is ideal for use in digital-encoder systems in the harsh environments of automotive or industrial applications. The A3422xKA is a high-sensitivity device optimized for use with high-density magnets.

The A3422xKA monolithic integrated circuit contains two independent Hall-effect latches whose digital outputs are internally coupled to CMOS logic circuitry that decodes signal speed and direction. Extremely low-drift BiCMOS circuitry is used for the amplifiers to ensure symmetry between the two latches so that signal quadrature can be
maintained. An on-chip voltage regulator allows the use of this device from a 4.5 V to 18 V supply. The outputs are standard open-collector outputs.

Two operating temperature ranges are provided; suffix 'E-' is for
the automotive and industrial temperature range of -40&#176;C to +85 &#176;C,
suffix 'L-' is for the automotive and military temperature range of
-40&#176;C to +150&#176;C. The 5-pin 'KA' SIP package provides a cost competitive
solution to magnetic sensing in harsh environments.

(:table border=0 cellpadding=5 cellspacing=5 align=center:)
(:cell:)
|| border=1
||! MAXIMUM RATINGS !||
||Supply Voltage, VCC || 18 V ||
||Magnetic Flux Density, B || Unlimited ||
||Output OFF Voltage, VOUT || VCC ||
||Output Sink Current, IOUT || 30 mA ||
||Package Power Dissipation, PD || 500 mW ||
||Operating Temperature Range, TA ||||
||Suffix 'E-' || -40&#730;C to +85&#730;C ||
||Suffix 'L-' || -40&#730;C to +150&#730;C ||
|| Storage Temperature Range, TS || -65&#730;C to +170&#730;C ||

(:cell:) http://itp.nyu.edu/~jg1646/sensors/pinout.gif
(:tableend:)
to:
This sensor is able to handle such a range of voltage (4.5V to 18V) because of a regulater that's built onto the chip. When I first wired the board for this sensor I tried using the power from the rest of the board (using a 5V regulator). I wasn't getting any readings from the sensor even though testing the wires with a multimeter indicated there were 5V going in. I believe that one of the features of the sensor, the under-voltage lockout, was preventing the sensor from turning on. Once I gave it 12V though I started getting readings.
Added lines 155-160:

The datasheet discusses a "quadrature relationship" that needs to be maintained between the sensor and the magnet and I think this is where I'm running into problems. According to a formula they give, the spacing requirements can be satisfied if nT/4 = 1.5 mm, where T is the period of the magnetic field and n is an odd integer. For an example it is stated "ring magnets with pole-pair spacing equal to 6 mm (n = 1), 2 mm (n = 3), 1.2 mm (n = 5), etc. are permitted."
Here is my attempt at checking the magnets I have against this:
Attach: quadrature.jpg
Changed lines 133-135 from:
!!!!Typical Magnetic Characteristics %center% http://itp.nyu.edu/~jg1646/sensors/magnetic.gif
to:
Deleted lines 48-50:
%center% http://itp.nyu.edu/~jg1646/sensors/functional.gif
Deleted lines 157-162:
%center% http://itp.nyu.edu/~jg1646/sensors/powerdiss.gif

!!!!Typical Electrical Characteristics %center% http://itp.nyu.edu/~jg1646/sensors/electrical.gif

%center% http://itp.nyu.edu/~jg1646/sensors/electricalB.gif
Changed line 176 from:
between the ring magnet pole width (pole being North or South), the sensor-tosensor spacing, and, to a lesser extent, the magnetic switch points. For optimal design, the sensor should be actuated with a ring magnet pole width* two times
to:
between the ring magnet pole width (pole being North or South), the sensor-to-sensor spacing, and, to a lesser extent, the magnetic switch points. For optimal design, the sensor should be actuated with a ring magnet pole width* two times
Deleted lines 196-207:

!!!!Operation with Fine-Pitch Ring Magnets
For targets with a circular pitch of less than 4 mm, a performance improvement can be observed by rotating
the front face of the sensor subassembly (see below). This sensor rotation decreases the effective
sensor-to-sensor spacing, provided that the Hall elements are not rotated beyond the width of the
target.



!!!!Rotated Sensor for Fine-Pitch Ring Magnets %center% http://itp.nyu.edu/~jg1646/sensors/rotated.gif
Added lines 166-167:
[[Attach:magnets.jpg]]
Changed lines 204-212 from:
!!!!!Applications
It is strongly recommended that an external 0.01 &#956;F bypass capacitor be connected (in
close proximity to the Hall sensor) between the supply and ground of the device to reduce both
external noise and noise generated by the internal logic. The simplest form of magnet that will operate
these devices is a ring magnet. Other methods of operation, such as linear magnets, are possible.
Extensive applications information on magnets and Hall-effect sensors is also available in the "Hall-
Effect IC Applications Guide" which can be found in the latest issue of Application Note 27701, at
www.allegromicro.com/techpub2/an/an27701
to:
Deleted lines 210-212:

!!!!Dimensions in Inches
%center% http://itp.nyu.edu/~jg1646/sensors/dimensions.gif
Changed lines 1-2 from:
otThis summary covers the A3422xKA Hall-effect, direction-detection sensor from [[http://allegromicro.com/sf/3421/ | Allegro Microsystems, Inc. ]] The data sheet can be found [[ http://allegromicro.com/datafile/3421.pdf | here]].
to:
This sensor report covers the A3422xKA Hall-effect, direction-detection sensor from [[http://allegromicro.com/sf/3421/ | Allegro Microsystems, Inc. ]] The data sheet can be found [[ http://allegromicro.com/datafile/3421.pdf | here]]. I received samples and was not able to find the cost of purchase.

Like other hall effect sensors, as mentioned in John Schimmel's datasheet, this one also detects a magnetic field and acts as a switch (on/off state). However, it also has the unique capability of being able to determine the direction that the magnet (Allegro recommends a ring one)is rotating (as you might have guessed by the name). This built in capability is what interested me in the sensor. Although you could accomplish the same goal yourself by using two hall sensors and calculate the direction by which sensor passes you first, Allegro Microsystems has already done the job for you in a very precise way.

The sensor comes with two aligned hall elements inside of it. And although Hall effect sensors are usually used in harsh environments (not affected by dirt like an optical sensor, and using the magnetic field means there's no need for contact), this one seems especially sturdy. There are two versions of the 3422, the

Applications
Automotive (e.g. tachometer)
Industrial
Changed lines 19-23 from:
The A3422xKA Hall-effect is capable of sensing the direction of rotation of a ring magnet. This transducer
provides separate digital outputs that provide information on magnet rotation speed, direction, and magnet pole count. It allows for fine-pitch direction-detection applications by maintaining accurate mechanical
location between the two active Hall elements. The two Hall elements are photolithographically aligned to better than 1 &#956;m, as contrasted with 100 &#956;m or worse mechanical location tolerance when
manufactured discretely.
This highly sensitive, temperature-stable, magnetic transducer is ideal for use in digital-encoder systems in the harsh environments of automotive or industrial applications. The A3422xKA is a high-sensitivity device optimized for use with high-density magnets.
to:

This
highly sensitive, temperature-stable, magnetic transducer is ideal for use in digital-encoder systems in the harsh environments of automotive or industrial applications. The A3422xKA is a high-sensitivity device optimized for use with high-density magnets.
Changed lines 164-170 from:
!!!Functional Description
The integrated circuit contains an internal voltage regulator
that powers the Hall sensors and both the
analog and digital circuitry
. This regulator allows operation over a wide supply voltage range and
provides some immunity to supply noise
. The device also contains CMOS logic circuitry that decodes the
direction of rotation of the ring magnet
.
to:
!!!!!Magnets
I purchased two types of magnets (both from Radioshack, maybe
that was part of the problem) to test out:
Ceramic magnet
http://www
.radioshack.com/product/index.jsp?productId=2102641&cp=&kw=magnets&parentPage=search

Rare earth magnet
http://www
.radioshack.com/product/index.jsp?productId=2102642&cp=&pg=1&kw=magnets&parentPage=search
Changed lines 1-2 from:
This summary covers the A3422xKA Hall-effect, direction-detection sensor from [[http://allegromicro.com/sf/3421/ | Allegro Microsystems, Inc. ]] The data sheet can be found [[ http://allegromicro.com/datafile/3421.pdf | here]].
to:
otThis summary covers the A3422xKA Hall-effect, direction-detection sensor from [[http://allegromicro.com/sf/3421/ | Allegro Microsystems, Inc. ]] The data sheet can be found [[ http://allegromicro.com/datafile/3421.pdf | here]].
Changed lines 13-15 from:
location between the two active Hall elements. The two Hall elements are photolithographically aligned to better than 1 m, as contrasted with 100 m or worse mechanical location tolerance when
manufactured discretely. This highly sensitive, temperature-stable, magnetic transducer is ideal for use in digital-encoder systems in the harsh environments of automotive or industrial applications. The A3422xKA is a high-sensitivity device optimized for use with highdensity magnets.
to:
location between the two active Hall elements. The two Hall elements are photolithographically aligned to better than 1 &#956;m, as contrasted with 100 &#956;m or worse mechanical location tolerance when
manufactured discretely. This highly sensitive, temperature-stable, magnetic transducer is ideal for use in digital-encoder systems in the harsh environments of automotive or industrial applications. The A3422xKA is a high-sensitivity device optimized for use with high-density magnets.
Changed lines 19-22 from:
Two operating temperature ranges are provided; suffix EC is for
the automotive and industrial temperature range of -40C to +85C,
suffix LC
is for the automotive and military temperature range of
-40C to +150C. The 5-pin KA SIP package provides a cost competitive
to:
Two operating temperature ranges are provided; suffix 'E-' is for
the automotive and industrial temperature range of -40&#176;C to +85 &#176;C,
suffix 'L-'
is for the automotive and military temperature range of
-40&#176;C to +150&#176;C. The 5-pin 'KA' SIP package provides a cost competitive
Changed lines 35-36 from:
||Suffix EC || -40&#730;C to +85&#730;C ||
||Suffix LC || -40&#730;C to +150&#730;C ||
to:
||Suffix 'E-' || -40&#730;C to +85&#730;C ||
||Suffix 'L-' || -40&#730;C to +150&#730;C ||
Changed lines 168-169 from:
the sensor-to-sensor spacing. This will produce a sinusoidal magnetic field whose period (denoted as
)
to:
the sensor-to-sensor spacing. This will produce a sinusoidal magnetic field whose period (denoted as T)
Changed lines 170-171 from:
ring magnet that has a period that satisfies the relationship n
/4 = 1.5 mm, where n is any odd integer.
to:
ring magnet that has a period that satisfies the relationship nT/4 = 1.5 mm, where n is any odd integer.
Changed line 177 from:
E1 to E2 and ON (low) for the direction E2 to E1. SPEED provides an XORd output of the two sensors.
to:
E1 to E2 and ON (low) for the direction E2 to E1. SPEED provides an XOR'd output of the two sensors.
Changed line 196 from:
It is strongly recommended that an external 0.01 F bypass capacitor be connected (in
to:
It is strongly recommended that an external 0.01 &#956;F bypass capacitor be connected (in
Changed lines 200-201 from:
Extensive applications information on magnets and Hall-effect sensors is also available in the Hall-
Effect IC Applications Guide which can be found in the latest issue of Application Note 27701, at
to:
Extensive applications information on magnets and Hall-effect sensors is also available in the "Hall-
Effect IC Applications Guide" which can be found in the latest issue of Application Note 27701, at
Changed line 209 from:
%center% !!!!Sensor Locations
to:
!!!!Sensor Locations
Deleted lines 205-206:
!!!!Rotated Sensor for Fine-Pitch Ring Magnets %center% http://itp.nyu.edu/~jg1646/sensors/locations.gif
Added lines 207-213:


%center% !!!!Sensor Locations
%center% http://itp.nyu.edu/~jg1646/sensors/locations.gif

!!!!Dimensions in Inches
%center% http://itp.nyu.edu/~jg1646/sensors/dimensions.gif
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!!!!Rotated Sensor for Fine-Pitch Ring Magnets %center% http://itp.nyu.edu/~jg1646/sensors/locations.gif
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!!!!Rotated Sensor for Fine-Pitch Ring Magnets %center% http://itp.nyu.edu/~jg1646/sensors/rotated.gif
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to:
!!!!Rotated Sensor for Fine-Pitch Ring Magnets %center% http://itp.nyu.edu/~jg1646/sensors/rotated.gif
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!!!!!!Sensor Locations

%center% http://itp.nyu.edu/~jg1646/sensors/locations.gif

!!Dimensions in Inches
%center% http://itp.nyu.edu/~jg1646/sensors/dimensions.gif
to:
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!!!!Sensor Locations
to:
!!!!!!Sensor Locations
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!!!!Dimensions in Inches
to:
!!Dimensions in Inches
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!!!!Sensor Locations %center% http://itp.nyu.edu/~jg1646/sensors/locations.gif

!!!!Dimensions in Inches %center% http://itp.nyu.edu/~jg1646/sensors/dimensions.gif
to:
!!!!Sensor Locations

%center% http://itp.nyu.edu/~jg1646/sensors/locations.gif

!!!!Dimensions in Inches
%center% http://itp.nyu.edu/~jg1646/sensors/dimensions.gif
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Deleted line 209:
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!!!!Sensor Locations
%center% http://itp.nyu.edu/~jg1646/sensors/locations.gif


!!!!Dimensions in Inches
%center% http://itp.nyu.edu/~jg1646/sensors/dimensions.gif
to:
!!!!Sensor Locations %center% http://itp.nyu.edu/~jg1646/sensors/locations.gif


!!!!Dimensions in Inches %center% http://itp.nyu.edu/~jg1646/sensors/dimensions.gif
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%center%!!!!Sensor Locations
to:
!!!!Sensor Locations
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%center%!!!!Dimensions in Inches
to:
!!!!Dimensions in Inches
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!!!!Sensor Locations %center% http://itp.nyu.edu/~jg1646/sensors/locations.gif


!!!!Dimensions in Inches %center% http://itp.nyu.edu/~jg1646/sensors/dimensions.gif
to:
%center%!!!!Sensor Locations
%center% http://itp.nyu.edu/~jg1646/sensors/locations.gif


%center%!!!!Dimensions in Inches
%center% http://itp.nyu.edu/~jg1646/sensors/dimensions.gif
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!!!!Sensor Locations %center%http://itp.nyu.edu/~jg1646/sensors/locations.gif


!!!!Dimensions in Inches %center%http://itp.nyu.edu/~jg1646/sensors/dimensions.gif
to:
!!!!Sensor Locations %center% http://itp.nyu.edu/~jg1646/sensors/locations.gif


!!!!Dimensions in Inches %center% http://itp.nyu.edu/~jg1646/sensors/dimensions.gif
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!!!!Sensor Locations %center% http://itp.nyu.edu/~jg1646/sensors/locations.gif
to:
!!!!Sensor Locations %center%http://itp.nyu.edu/~jg1646/sensors/locations.gif
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!!!!Sensor Locations %center%http://itp.nyu.edu/~jg1646/sensors/rotated.gif
to:
!!!!Sensor Locations %center% http://itp.nyu.edu/~jg1646/sensors/locations.gif
Changed lines 125-128 from:
NOTES:1. Magnetic flux density is measured at most sensitive area of device, nominally located 0.0165 (0.42 mm) below the branded face of the package.
2. Typical Data is at VCC = 12 V and TA = +25C and is for design information only.
3. As used here, negative flux densities are defined as less than zero (algebraic convention).
to:
NOTES:\\
1. Magnetic flux density is measured at most sensitive area of device, nominally located 0.0165 (0.42 mm) below the branded face of the package.\\
2. Typical Data is at VCC = 12 V and TA = +25C and is for design information only.\\
3. As used here, negative flux densities are defined as less than zero (algebraic convention).\\
Changed lines 148-151 from:
NOTES:
1. Maximum supply voltage must be adjusted for power dissipation and ambient temperature.
2. Typical Data is at VCC = 12 V and TA = +25C and is for design information only.
to:
NOTES: \\
1.
Maximum supply voltage must be adjusted for power dissipation and ambient temperature.\\
2. Typical Data is at VCC = 12 V and TA = +25C and is for design information only.\\
Changed line 50 from:
(:table border=1 cellpadding=5 cellspacing=0:)
to:
(:table border=1 cellpadding=5 cellspacing=0 align=center:)
Changed line 133 from:
|| border = 1
to:
|| border = 1 align=center
Changed lines 125-126 from:
NOTES:1. Magnetic flux density is measured at most sensitive area of device,
nominally located 0.0165 (0.42 mm) below the branded face of the package.
to:
NOTES:1. Magnetic flux density is measured at most sensitive area of device, nominally located 0.0165 (0.42 mm) below the branded face of the package.
Changed lines 147-148 from:
NOTES:1. Maximum supply voltage must be adjusted for power dissipation and ambient temperature.
to:
NOTES:
1. Maximum supply voltage must be adjusted for power dissipation and ambient temperature.
Changed line 77 from:
(:cellnr:)TA = -40C
to:
(:cell:)TA = -40C
Changed line 76 from:
(:cell: (rowspan=3))BRP
to:
(:cell rowspan=3:)BRP
Changed line 93 from:
(:cell: rowspan=3:)Bhys
to:
(:cell rowspan=3:)Bhys
Changed line 59 from:
(:cell: (rowspan=3))BOP
to:
(:cell rowspan=3:)BOP
Changed line 75 from:
(:cellnr (rowspan=3):)Release Point3
to:
(:cellnr rowspan=3:)Release Point3
Changed lines 92-93 from:
(:cellnr: (rowspan=3))Hysteresis
(:cell: (rowspan=3))Bhys
to:
(:cellnr rowspan=3:)Hysteresis
(:cell: rowspan=3:)Bhys
Changed line 58 from:
(:cellnr: (rowspan=3))Operate Point
to:
(:cellnr rowspan=3:)Operate Point
Changed line 75 from:
(:cellnr: (rowspan=3))Release Point3
to:
(:cellnr (rowspan=3):)Release Point3
Added lines 49-129:
!!!MAGNETIC CHARACTERISTICS over operating voltage range.
(:table border=1 cellpadding=5 cellspacing=0:)
(:cell:) Characteristic
(:cell:) Symbol
(:cell:) Test Conditions
(:cell:) Min.
(:cell:) Typ.
(:cell:) Max.
(:cell:) Units
(:cellnr: (rowspan=3))Operate Point
(:cell: (rowspan=3))BOP
(:cell:) TA = -40C
(:cell:)
(:cell:)
(:cell:) 85
(:cell:) G
(:cellnr:)TA = +25C
(:cell:)
(:cell:)29
(:cell:)75
(:cell:)G
(:cellnr:) TA = Maximum
(:cell:)
(:cell:)
(:cell:)75
(:cell:)G
(:cellnr: (rowspan=3))Release Point3
(:cell: (rowspan=3))BRP
(:cellnr:)TA = -40C
(:cell:)-85
(:cell:)
(:cell:)
(:cell:)G
(:cellnr:)TA = +25C
(:cell:)-75
(:cell:)-17
(:cell:)
(:cell:)G
(:cellnr:)TA = Maximum
(:cell:)-75
(:cell:)
(:cell:)
(:cell:)G
(:cellnr: (rowspan=3))Hysteresis
(:cell: (rowspan=3))Bhys
(:cell:)TA = -40C
(:cell:)10
(:cell:)
(:cell:)
(:cell:)G
(:cellnr:)TA = +25C
(:cell:)10
(:cell:)46
(:cell:)
(:cell:)G
(:cellnr:)TA = Maximum
(:cell:)10
(:cell:)
(:cell:)
(:cell:)G
(:cellnr:)Operate Differential
(:cell:)
(:cell:)BOP1 - BOP2
(:cell:)
(:cell:)
(:cell:)60
(:cell:)G
(:cellnr:)Release Differential
(:cell:)
(:cell:) BRP1 - BRP2
(:cell:)
(:cell:)
(:cell:) 60
(:cell:) G
(:tableend:)

NOTES:1. Magnetic flux density is measured at most sensitive area of device,
nominally located 0.0165 (0.42 mm) below the branded face of the package.
2. Typical Data is at VCC = 12 V and TA = +25C and is for design information only.
3. As used here, negative flux densities are defined as less than zero (algebraic convention).
Deleted line 132:
Changed lines 135-149 from:
Limits
||! Characteristic ||! Symbol ||! Test Conditions ||!Min. ||!Typ. ||!Max. ||! Units
Supply Voltage Range VCC Operating, TJ < 165C1 4.5 18 V
Output Leakage Current IOFF VOUT = VCC =
18 V <1.0 10 &#956;A
Output Saturation Voltage VOUT(SAT) IOUT = 20 mA 0.21 0.50
V
Power-On State POS VCC = 0 &#8594; 5 V, OFF OFF OFF
BRP1 < B < BOP1, BRP2 < B < BOP2
Undervoltage Lockout VCC(UV) IOUT = 20 mA, VCC = 0 &#8594; 5 V3.5 V
Undervoltage Hysteresis VCC(hys) Lockout (VCC(UV)) - Shutdown0.5 V
Power-On Time tpo VCC > 4.5 V 50 &#956;s
Output Rise Time tr CL = 20 pF, RL = 820 &#937; 200 ns
Output Fall Time tf CL = 20 pF, RL = 820 &#937; 200
ns
Direction Change Delay td CL = 20 pF, RL = 820 &#937; 0.5 1.0 5.0 &#956;s
Supply Current ICC VCC = 8
V, All outputs OFF 5.0 9.0 18 mA
ELECTRICAL CHARACTERISTICS over operating temperature range
.
to:
||! Characteristic ||! Symbol ||! Test Conditions ||!Min. ||!Typ. ||!Max. ||! Units ||
|| Supply Voltage Range || VCC || Operating, TJ < 165C1 || 4.5
|| || 18 || V ||
|| Output Leakage Current || IOFF || VOUT = VCC = 18
V || || <1.0 ||10 || &#956;A ||
|| Output Saturation Voltage || VOUT(SAT) || IOUT = 20 mA || || 0.21 || 0.50 || V ||
|| Power-On State || POS || VCC = 0 &#8594; 5 V, BRP1 < B < BOP1, BRP2 < B < BOP2 || OFF || OFF || OFF || ||
|| Undervoltage Lockout || VCC(UV) || IOUT = 20 mA, VCC = 0 &#8594; 5 V || || 3.5 ||
|| V ||
|| Undervoltage Hysteresis || VCC(hys) || Lockout (VCC(UV)) - Shutdown || || 0.5 || ||
V ||
|| Power-On Time || tpo || VCC > 4.5 V || || || 50 || &#956;s ||
|| Output Rise Time || tr || CL = 20 pF, RL = 820 &#937; || || 200 || || ns ||
|| Output Fall Time || tf || CL = 20 pF, RL = 820 &#937; || || 200 || || ns ||
|| Direction Change Delay || td || CL = 20 pF, RL = 820 &#937; || 0
.5 || 1.0 || 5.0 || &#956;s ||
|| Supply Current || ICC || VCC = 8 V, All outputs OFF || 5.0 || 9.0 || 18 || mA ||
Added line 150:
Added lines 52-73:

!!!ELECTRICAL CHARACTERISTICS over operating temperature range.
|| border = 1
Limits
||! Characteristic ||! Symbol ||! Test Conditions ||!Min. ||!Typ. ||!Max. ||! Units
Supply Voltage Range VCC Operating, TJ < 165C1 4.5 18 V
Output Leakage Current IOFF VOUT = VCC = 18 V <1.0 10 &#956;A
Output Saturation Voltage VOUT(SAT) IOUT = 20 mA 0.21 0.50 V
Power-On State POS VCC = 0 &#8594; 5 V, OFF OFF OFF
BRP1 < B < BOP1, BRP2 < B < BOP2
Undervoltage Lockout VCC(UV) IOUT = 20 mA, VCC = 0 &#8594; 5 V3.5 V
Undervoltage Hysteresis VCC(hys) Lockout (VCC(UV)) - Shutdown0.5 V
Power-On Time tpo VCC > 4.5 V 50 &#956;s
Output Rise Time tr CL = 20 pF, RL = 820 &#937; 200 ns
Output Fall Time tf CL = 20 pF, RL = 820 &#937; 200 ns
Direction Change Delay td CL = 20 pF, RL = 820 &#937; 0.5 1.0 5.0 &#956;s
Supply Current ICC VCC = 8 V, All outputs OFF 5.0 9.0 18 mA
ELECTRICAL CHARACTERISTICS over operating temperature range.
NOTES:1. Maximum supply voltage must be adjusted for power dissipation and ambient temperature.
2. Typical Data is at VCC = 12 V and TA = +25C and is for design information only.
%center% http://itp.nyu.edu/~jg1646/sensors/powerdiss.gif
Changed lines 89-90 from:
!!!Applications Information
!!!!Operation
with Fine-Pitch Ring Magnets.
to:
!!!!Operation with Fine-Pitch Ring Magnets
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!!!!Sensor Locations %center%http://itp.nyu.edu/~jg1646/sensors/rotated.gif
to:
!!!!Sensor Locations %center%http://itp.nyu.edu/~jg1646/sensors/rotated.gif

!!!!Dimensions in Inches %center%http://itp.nyu.edu/~jg1646/sensors/dimensions
.gif
Changed line 63 from:
!!!!Quadrature/Direction Detection.
to:
!!!!!Quadrature/Direction Detection
Changed line 74 from:
!!!!Outputs.
to:
!!!!!Outputs
Changed line 82 from:
!!!!Power-On State.
to:
!!!!!Power-On State
Changed line 96 from:
!!!!Applications.
to:
!!!!!Applications
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!!!!Rotated Sensor for Fine-Pitch Ring Magnets %center% http://itp.nyu.edu/~jg1646/sensors/rotated.gif
to:
!!!!Rotated Sensor for Fine-Pitch Ring Magnets %center% http://itp.nyu.edu/~jg1646/sensors/rotated.gif


!!!!Sensor Locations %center%
http://itp.nyu.edu/~jg1646/sensors/rotated.gif
Changed line 105 from:
%center% http://itp.nyu.edu/~jg1646/sensors/rotated.gif
to:
!!!!Rotated Sensor for Fine-Pitch Ring Magnets %center% http://itp.nyu.edu/~jg1646/sensors/rotated.gif
Changed line 13 from:
location between the two active Hall elements. The two Hall elements are photolithographically aligned to better than 1 m, as contrasted with 100 m or worse mechanical location tolerance when
to:
location between the two active Hall elements. The two Hall elements are photolithographically aligned to better than 1 m, as contrasted with 100 m or worse mechanical location tolerance when
Changed lines 19-22 from:
Two operating temperature ranges are provided; suffix E is for
the automotive and industrial temperature range of -40C to +85C,
suffix L is for the automotive and military temperature range of
-40C to +150C. The 5-pin KA SIP package provides a cost competitive
to:
Two operating temperature ranges are provided; suffix EC is for
the automotive and industrial temperature range of -40C to +85C,
suffix LC is for the automotive and military temperature range of
-40C to +150C. The 5-pin KA SIP package provides a cost competitive
Changed lines 35-36 from:
||Suffix E || -40&#730;C to +85&#730;C ||
||Suffix L || -40&#730;C to +150&#730;C ||
to:
||Suffix EC || -40&#730;C to +85&#730;C ||
||Suffix LC || -40&#730;C to +150&#730;C ||
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%center% http://itp.nyu.edu/~jg1646/sensors/electricalB.gif
to:
%center% http://itp.nyu.edu/~jg1646/sensors/electricalB.gif


!!!Functional Description
The integrated circuit contains an internal voltage regulator that powers the Hall sensors and both the
analog and digital circuitry. This regulator allows operation over a wide supply voltage range and
provides some immunity to supply noise. The device also contains CMOS logic circuitry that decodes the
direction of rotation of the ring magnet.

!!!!Quadrature/Direction Detection.
Internal logic circuitry provides outputs representing speed and direction of the magnetic field across the face of the package. For the direction signal to be appropriately updated, a quadrature relationship must be maintained
between the ring magnet pole width (pole being North or South), the sensor-tosensor spacing, and, to a lesser extent, the magnetic switch points. For optimal design, the sensor should be actuated with a ring magnet pole width* two times
the sensor-to-sensor spacing. This will produce a sinusoidal magnetic field whose period (denoted as
)
is then four times the sensor-to-sensor spacing. A quadrature relationship can also be maintained for a
ring magnet that has a period that satisfies the relationship n
/4 = 1.5 mm, where n is any odd integer.
Therefore, ring magnets with pole-pair spacing equal to 6 mm (n = 1), 2 mm (n = 3), 1.2 mm (n = 5), etc.
are permitted.

!!!!Outputs.
The device provides three saturated outputs: DIRECTION, E1 OUTPUT, and SPEED.
DIRECTION provides the direction output of the sensor and is defined as OFF (high) for the direction
E1 to E2 and ON (low) for the direction E2 to E1. SPEED provides an XORd output of the two sensors.
Because of internal delays, DIRECTION will always be updated before SPEED and is updated at every
transition of E1 OUTPUT and E2 OUTPUT (internal) allowing the use of up-down counters without the loss
of pulses.

!!!!Power-On State.
At power on, the logic circuitry is reset to provide an OFF (high) at DIRECTION and an
OFF (high) for E1 and E2 (internal) for magnetic fields less than BOP. This eliminates ambiguity when
the device is powered up and either sensor detects a field between BOP and BRP. If either sensor is subjected
to a field greater than BOP, the internal logic will set accordingly.


!!!Applications Information
!!!!Operation with Fine-Pitch Ring Magnets.
For targets with a circular pitch of less than 4 mm, a performance improvement can be observed by rotating
the front face of the sensor subassembly (see below). This sensor rotation decreases the effective
sensor-to-sensor spacing, provided that the Hall elements are not rotated beyond the width of the
target.

!!!!Applications.
It is strongly recommended that an external 0.01 F bypass capacitor be connected (in
close proximity to the Hall sensor) between the supply and ground of the device to reduce both
external noise and noise generated by the internal logic. The simplest form of magnet that will operate
these devices is a ring magnet. Other methods of operation, such as linear magnets, are possible.
Extensive applications information on magnets and Hall-effect sensors is also available in the Hall-
Effect IC Applications Guide which can be found in the latest issue of Application Note 27701, at
www.allegromicro.com/techpub2/an/an27701

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!!!!Typical Electrical Characteristics %center% http://itp.nyu.edu/~jg1646/sensors/electrical.gif

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.gif
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!!!!Magnetic Characteristics %center% http://itp.nyu.edu/~jg1646/sensors/magnetic.gif
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!!!!Typical Magnetic Characteristics %center% http://itp.nyu.edu/~jg1646/sensors/magnetic.gif


!!!!Typical Electrical Characteristics %center% http://itp.nyu.edu/~jg1646/sensors/electrical
.gif
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!!!!Magnetic Characteristics
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!!!!Magnetic Characteristics %center% http://itp.nyu.edu/~jg1646/sensors/magnetic.gif
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!!!!Magnetic Characteristics
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.gif
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-40C to +150C. The 5-pin KA SIP package provides a costcompetitive
to:
-40C to +150C. The 5-pin KA SIP package provides a cost competitive
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(:cell:)
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(:tableend:)
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Changed lines 11-33 from:
The A3422xKA Hall-effect, direction-detection sensor is a new
generation
of special-function integrated sensors that is capable of
sensing the direction of rotation of a ring
magnet. This transducer
provides separate digital outputs that provide information on magnet
rotation speed,
direction, and magnet pole count. This device eliminates
the major manufacturing hurdles encountered in fine-pitch
direction-detection applications, namely maintaining accurate mechanical
location between the two active Hall elements. Here
, the two Hall
elements are photolithographically aligned to better than 1 m, as
contrasted with 100 m or worse mechanical location tolerance when
manufactured discretely. This highly sensitive, temperature-stable,
magnetic transducer is ideal for use in digital-encoder systems in the
harsh environments of automotive or industrial applications. The
A3422xKA is a high-sensitivity device optimized for use with highdensity
magnets.
The A3422xKA monolithic integrated circuit contains two independent
Hall-effect latches whose digital outputs are internally coupled to
CMOS logic circuitry that decodes signal speed and direction. Extremely
low-drift BiCMOS circuitry is used for the amplifiers to ensure
symmetry between the two latches so that signal quadrature can
be
maintained. An on-chip voltage regulator allows the use of this device
from a 4.5 V to 18 V supply. The outputs are standard open-collector
outputs.
to:
The A3422xKA Hall-effect is capable of sensing the direction of rotation of a ring magnet. This transducer
provides separate digital outputs that provide information on
magnet rotation speed, direction, and magnet pole count. It allows for fine-pitch direction-detection applications by maintaining accurate mechanical
location between
the two active Hall elements. The two Hall elements are photolithographically aligned to better than 1 m, as contrasted with 100 m or worse mechanical location tolerance when
manufactured discretely. This highly sensitive, temperature-stable, magnetic transducer is ideal for use in digital-encoder systems in the harsh environments of automotive or industrial applications. The A3422xKA is a high-sensitivity device optimized for use with highdensity magnets.

The A3422xKA monolithic integrated circuit contains two independent Hall-effect latches whose digital outputs are internally coupled to CMOS logic circuitry that decodes signal speed and direction. Extremely low-drift BiCMOS circuitry is used for the amplifiers to ensure symmetry between the two latches so that signal quadrature can
be
maintained. An on-chip voltage regulator allows the use of this device from a 4.5 V to 18 V supply. The outputs are standard open-collector outputs.
Deleted lines 24-25:
Changed lines 6-12 from:
^Temperature Stability
^4.5 V to 18 V Operation
^Electrically Defined Power-On State
^Under-Voltage Lockout
to:
*Temperature Stability
*4.5 V to 18 V Operation
*Electrically Defined Power-On State
*Under-Voltage Lockout

The A3422xKA Hall-effect, direction-detection sensor is a new
generation of special-function integrated sensors that is capable of
sensing the direction of rotation of a ring magnet. This transducer
provides separate digital outputs that provide information on magnet
rotation speed, direction, and magnet pole count. This device eliminates
the major manufacturing hurdles encountered in fine-pitch
direction-detection applications, namely maintaining accurate mechanical
location between the two active Hall elements. Here, the two Hall
elements are photolithographically aligned to better than 1 m, as
contrasted with 100 m or worse mechanical location tolerance when
manufactured discretely. This highly sensitive, temperature-stable,
magnetic transducer is ideal for use in digital-encoder systems in the
harsh environments of automotive or industrial applications. The
A3422xKA is a high-sensitivity device optimized for use with highdensity
magnets.
The A3422xKA monolithic integrated circuit contains two independent
Hall-effect latches whose digital outputs are internally coupled to
CMOS logic circuitry that decodes signal speed and direction. Extremely
low-drift BiCMOS circuitry is used for the amplifiers to ensure
symmetry between the two latches so that signal quadrature can be
maintained. An on-chip voltage regulator allows the use of this device
from a 4.5 V to 18 V supply. The outputs are standard open-collector
outputs.
Two operating temperature ranges are provided; suffix E is for
the automotive and industrial temperature range of -40C to +85C,
suffix L is for the automotive and military temperature range of
-40C to +150C. The 5-pin KA SIP package provides a costcompetitive
solution to magnetic sensing in harsh environments.
Changed lines 4-5 from:
^Internal Direction-Decoding Circuitry
^Two Matched Hall Latches On A Single Substrate
to:
*Internal Direction-Decoding Circuitry
*Two Matched Hall Latches On A Single Substrate
Changed lines 4-12 from:
'Internal Direction-Decoding Circuitry
'Two Matched Hall Latches On A Single Substrate
'Temperature Stability
'4.5 V to 18 V Operation
'Electrically Defined Power-On State
'Under-Voltage Lockout
to:
^Internal Direction-Decoding Circuitry
^Two Matched Hall Latches On A Single Substrate
^Temperature Stability
^4.5 V to 18 V Operation
^Electrically Defined Power-On State
^Under-Voltage Lockout
Changed lines 3-6 from:
to:
The main components of this sensor are:
'Internal Direction-Decoding Circuitry
'Two Matched Hall Latches On A Single Substrate
'Temperature Stability
'4.5 V to 18 V Operation
'Electrically Defined Power-On State
'Under-Voltage Lockout
Changed lines 1-6 from:
This summary covers the A3422xKA Hall-effect, direction-detection sensor from [[http://allegromicro.com/sf/3421/ | Allegro Microsystems, Inc. ]]
to:
This summary covers the A3422xKA Hall-effect, direction-detection sensor from [[http://allegromicro.com/sf/3421/ | Allegro Microsystems, Inc. ]] The data sheet can be found [[ http://allegromicro.com/datafile/3421.pdf | here]].
Added lines 1-6:
This summary covers the A3422xKA Hall-effect, direction-detection sensor from [[http://allegromicro.com/sf/3421/ | Allegro Microsystems, Inc. ]]



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|| Storage Temperature Range, TS || -65&#730;C to +170&#730;C ||
to:
|| Storage Temperature Range, TS || -65&#730;C to +170&#730;C ||

Attach:pinout.gif
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||Supply Voltage, VCC ||18 V ||
to:
||Supply Voltage, VCC || 18 V ||
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||Suffix E || -40&#730;C to +85&#730;C ||
to:
||Suffix E || -40&#730;C to +85&#730;C ||
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|| Supply Voltage, VCC ||18 V ||
to:
||Supply Voltage, VCC ||18 V ||
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||||Operating Temperature Range, TA ||
to:
||Operating Temperature Range, TA ||||
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|| Storage Temperature Range, TS || -65&#730;C to +170&#730;C ||
to:
|| Storage Temperature Range, TS || -65&#730;C to +170&#730;C ||
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||Operating Temperature Range, TA ||
to:
||||Operating Temperature Range, TA ||
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||Magnetic Flux Density, B || Unlimited ||
||Output OFF Voltage, VOUT || VCC ||
||Output Sink Current, IOUT || 30 mA ||
to:
||Magnetic Flux Density, B || Unlimited ||
||Output OFF Voltage, VOUT || VCC ||
||Output Sink Current, IOUT || 30 mA ||
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||Suffix E || -40&#730;C to +85&#730;C ||
||Suffix L ||
-40&#730;C to +150&#730;C ||
to:
||Suffix E || -40&#730;C to +85&#730;C ||
||Suffix L ||
-40&#730;C to +150&#730;C ||
Deleted lines 2-5:
|| cell 1 ||! cell 2 ||
|| cell 1 || cell 2 || cell 3 ||
Changed lines 1-12 from:
MAXIMUM RATINGS
Supply Voltage, VCC
18 V
Magnetic Flux Density, B
Unlimited
Output OFF
Voltage, VOUT VCC
Output Sink Current, IOUT
30 mA
Package Power Dissipation
,
PD 500 mW
Operating Temperature Range, TA

Suffix E -40&#730;C to +85&#730;C
Suffix L
-40&#730;C to +150&#730;C
Storage Temperature Range,
TS -65&#730;C to +170&#730;C
to:
|| border=1
||! MAXIMUM RATINGS !||
|| cell 1 ||! cell 2 ||
|| cell 1 || cell 2 ||
cell 3 ||


|| Supply
Voltage, VCC ||18 V ||
||Magnetic Flux Density, B ||
Unlimited ||
||Output OFF Voltage
, VOUT || VCC ||
||Output Sink Current, IOUT
|| 30 mA ||
||Package Power Dissipation, PD || 500 mW ||
||Operating Temperature Range, TA ||
||Suffix E ||
-40&#730;C to +85&#730;C ||
||Suffix L ||
-40&#730;C to +150&#730;C ||
|| Storage Temperature
Range, TS || -65&#730;C to +170&#730;C ||
Added lines 1-12:
MAXIMUM RATINGS
Supply Voltage, VCC 18 V
Magnetic Flux Density, B Unlimited
Output OFF Voltage, VOUT VCC
Output Sink Current, IOUT 30 mA
Package Power Dissipation,
PD 500 mW
Operating Temperature Range, TA
Suffix E -40&#730;C to +85&#730;C
Suffix L -40&#730;C to +150&#730;C
Storage Temperature Range,
TS -65&#730;C to +170&#730;C