Hello,
I have seen in few designs, even the microcontroller has internal power on reset, external power on reset IC are used? Do the internal feature is not reliable?
When we use external power on reset?
1. There are other devices to reset besides the MCU
2. The power supply start up might be (possibly) slow, so a configurable external POR chip makes sure of things; the MCU's POR might not handle a slow power ramp-up.
3. Other, dependent on the MCU in question.
P.s. should this post be in the Microcontroller forum, not analog design?