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AD8495 Break Detection (we need a neg output)

Question asked by cjlandry on Apr 21, 2011
Latest reply on Apr 21, 2011 by cjlandry

We are currently using an AD8495 with a K type thermocouple in our portable medical device.  The circuit works great...simple to use and easy to configure.  However, the recommended break detection configuration drives the output of the amplifier to the positive rail.  This works in many applications but unfortunately not in ours.  We want the output of the amplifier to go to GND when the thermocouple breaks or is open.  Any suggestions?

 

+Vs = 3.3vdc

-Vs = GND

Vref = GND

Sense is tied to the output

There is a 1M ohm resistor to GND at the thermocouple connector

 

Our circuit is exactly like figure 33 in the datasheet.

 

Thanks in advance!!

CJL

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