Other Parts Discussed in Thread: TLV713
I have an INA199A3 sensing a differential voltage of a few mV across a .001ohm resistor on an 18V line. The 18V line turns on around 100 milliseconds before the 3.3V power to the INA199. After about 15 hours of operation of a new board, the INA199 apparently exploded, breaking my 3.3V regulator (a TLV713 linear supply, fed by a 5V supply.) My theory is that the INA199 shorted its 18V inputs to the 3.3V Vcc, because I can't think of another way for it to break the TLV713 (the TLV713 has short-circuit protection, so I don't think a short to ground would have broken it.) Also, when I desoldered the INA199, the sense pins and the Vcc pin were burnt, but the GND and output pins were ok.
The problem happened a few seconds after powerup. As far as I can tell, it was a normal powerup like I've done ~30 times before with this board, and ~300 times before on other prototypes of this board design. Here's a picture of the INA199 after the failure:
The circuit follows the datasheet as far as I can tell; see below. The output just goes to a microcontroller through a 10k resistor (not shown).
Immediately after the failure, I verified that my 18V supply was in fact at 18V. I replaced the broken voltage regulator on the board, and everything worked fine. There's only about 0.1Vpp noise on the 3.3V line, so I don't think that is causing damage.
I'd prefer my INA199 to not explode, but my real concern is the damage to my 3.3V supply, because it takes down my microcontroller.
I'm inexperienced with current-sense amplifiers. Are there recommended ways to guard against this short-circuit failure mode that I should be doing? Is there an addendum to the datasheet that I haven't read? Are there good ways to mitigate the short circuit if it happens? For example, I'm considering putting the two INA199s on my board on a separate supply, powered through a 100ohm resistor.
