Other Parts Discussed in Thread: CC2640R2F, CC2640
Hello,
for a bidirectional current sensing application I'm using an INA181.
I'm sensing the current in- and outflow of a leadacid-battery, so approx. 12V. As a µC I use a CC2640R2F.
I applied 3.3V to VS, ~12V to IN+ and IN- and gave it as a reference the VDDR pin of the CC2640, which is ~1.7V, the output goes directly to an analog pin of the µC.
There are two problems occuring:
1. When my board is completely switched off, but the 12V on IN+ and IN- still applied, there is a Voltage on VDDS present, which I don't want. If switched off, the board is required to carry no voltage at all (but the 12V) .
2. After a while the INA181 heats up (you can't touch it with the finger), and eventually it broke due to overheating.
So my question is, is there anything I'm missing out on? I sticked to the datasheet as close as possible, but the INA181 shows the stated behaviour.
Maybe using the VDDR pin of the CC2640 as a reference was a mistake, would that explain it? Any suggestions on how to make it work on the prototype?