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Current source not working in AD7792

Question asked by apoorv on Jan 28, 2013
Latest reply on Feb 1, 2013 by apoorv

I have interfaced an AD7792 board (Self made prototype board) with Atmega328P. I want to use it for temperature sensing through RTD.

 

The serial interface is working fine (Read the ID register correctly) but for some reason the on-chip current sources doesn't seem to work. I have connected 470E resistor on IOUT1 and have configured the IO register (Value 0x03) so that 1mA is sourced on both IOUT1 & IOUT2.

 

I'm expecting to see 470 mV across the resistor, but I'm getting 33mV. I have tried making 2 of such boards to rule out possibility of bad chip or bad soldering,

 

I would really appreciate if I can get some help on debugging it.

 

Thanks in advance.

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