Other Parts Discussed in Thread: TINA-TI
Hi,
I marked the former question/issue as resolved bit then i thought of it again and I would like to reopen it.. I replied to the last answer, but may be it went missing somehow.
original post was called: " INA381: Can an RC filter (1ms) be placed between Vout and CMPin"
So i'll open it again:
after presenting the solution to a colleague, he also pointed out that there may be issues with the thresholds for the GPIOs (Vih / Vil may very between parts (same component). Also, this may be affected by temperature..
So I went over the datasheet again and found a section that i have missed:
"8.1.4 Input Filtering
If the INA381 output is connected to a high-impedance input, the device output is the best location to filter, using a simple RC network from VOUT to GND. Filtering at the output attenuates high-frequency disturbances in the common-mode voltage, differential input signal, and INA381 power-supply voltage. "
this brings me back to my original idea.. It seems to even be a recommended practice.
I tried reading the "Closed-Loop Analysis of Load-Induced Amplifier Stability Issues Using ZOUT", it is a bit complicated. I also tried to simulate this using the PSpice for TI but the part is missing from the database.
1) Actually, I'm adding an RC load with no real inductive elements. and as long as R is large enough, i don't see stability / ringing risks. Correct?
2) I thought of RC = 10K * 10nF = 100usec to start with.
3) or, should i use a 1nF (max output load - No sustained oscillation according to the DS) and a 100K?
this will probably add an hysteresis of ~100mV (according to table 3)
Please advise.
Thank you,
Cha