The Absolute Maximum rating of I/O pin voltage for VI/O, VDD ≤3.6 V is -0.3V to VDD + 0.3V in Table 185. We would like to monitor the battery voltage using an AIN pin because we are planning to use a regulator for the board. During power-up/power-down and in case of a power supply short to ground the voltage on the AIN pin may higher than VDD + 0.3V. Is there a current limit for AIN pins that will prevent damage? If yes, will a series 200K resistor connected to the battery satisfy the current limit?
