Other Parts Discussed in Thread: INA220
Hello. Some of these questions might have already been addressed, but after a quick search I couldn't find anything.
I'd like to use the INA219 in an project I'm working on and so far it seems to be working pretty well. I have a few questions before I decide though.
1. The INA219 is advertised as a high side current monitor, but is there any reason I can't use it as a low side monitor? In my application, I have the chip set to the 320 mV FSR, and I'm using it to sense a 4 - 20 mA signal across a 10 ohm shunt resistor. I've tested it on the low side and it seems to work fine. I understand the INA220 is almost identical, and can also be used on the low side, but it's slightly more expensive. So, is the INA219 just less accurate on the low side because of the lower common mode voltage, or is there another reason it's not advertised to work on the low side too?
2. I'm planning on protecting the inputs with a TVS diode and RC filter like the datasheet describes, but when I tried to breadboard the RC filter the reported measurements became very inaccurate and unpredictable. I used a 10 ohm resistor in series with each input, and a 100 nF capacitor across them just like it's shown in the datasheet. This was with the same 10 ohm shunt resistor. My question is, can the inaccuracy be explained by input resistors that weren't evenly matched (either because of the tolerance or the solderless breadboard)? Or, are problems created when the series input resistors are close in value to the shunt resistor? In the datasheet, the shunt resistor is in the milliohm range, so the input resistors (10 ohms) are orders of magnitude above that.
3. What is the significance of the 'A' and 'B' suffix in the part number? I'd like to choose the part that is more ESD resilient, and can tolerate more/greater dV/dt events. Does this suffix have anything to do with that?
Thanks in advance for any help you can provide.