I designed system thats monitoring batteries discharging.
There are a lot of batteries sampled by AMP03 (Unity gain, diff. amp) then transfered via 2 analog 32-1 MUX (ADG732) and analog MUX 2-1 (ADG1219) and finally driven through the another unity gain amp to NI A/D in the PC.
After some months of working the battery sample amps started to burn up at random order.
May I miss anything in the design, espessialy in AMP-MUX interface?
Thank you for your response.
The AMP03 is not Instrumental Amp, but precision unity gain diff amp.
you can see the whole datasheet here http://www.analog.com/en/products/amplifiers/specialty-amplifiers/current-sense-amplifiers/amp03.html
There are internal resistors inside the component. I connected the AMP like described in application circuits:
What happens sometimes is that the mux input (connected to AMP03 output) is stuck in -0.5V, I suppose that's clamped by internal diode.
I tried to add a series resistor between Amp and MUX (100R, 1K, 10K)
I tried to connect Amp like a summing Amp (E1=E2=Battery => gain = 2) and on output I put voltage divider (two 10K resistors)
So that's working, but when I connected it to MUX I get -0.5V in the MUX input, WHY?