Hi,
I am currently having a problem with a MSP430FR2433 resetting, possibly due to a voltage drop on the supply pin. When a load (2 LDOs and a load switch, about 500 mA) is enabled through the MCU (or manually triggered), the MCU resets. However, the output port (3.0) which enables the load continues to stay high through the reset, so it only happens once.
Supply voltage is 3.377 V and the drop goes down to 2.882 V:
From what I can understand, it is the Supply Voltage Supervisor (SVS) or BOR that causes the reset (5.11.1 in datasheet).
I have tried to add an additional electrolytic capacitor (470µF) at the input of the circuit. Not an optimal position, but board is very small and hard to modify. This reduces the drop to 3.051 V, at a rate just under 0.1V/µs (should be safe from BOR reset due to V change). Without the additional capacitor, the drop is 2.882 V at a rate close to 0.2V/µs (close to BOR trigger).
I am currently running the MCU in LPM0 (SVS active) and have tried lower clock speed without any change (down to 6 Mhz).
Is it possible to adjust the SVS (or BOR) to handle this voltage drop, if so how? Or any other recommendation to resolve my issue?
I followed the recommendation from the datasheet about capacitors at Vcc pin (10µF and 0.1µF), but considering increasing the 10µF capacitor value (size 0805, restricted to maximum 100µF), and possibly the capacitors I have in front of the LDOs.