A brown-out detector and power-on-reset circuit can be used to monitor a supply voltage to determine when brown-out and power-on events occur and provide the appropriate reset signal in response. The circuit can include a comparator to generate the reset signal and a first monitoring circuit that operates in conjunction with a second monitoring circuit to provide an input voltage to the comparator. The first monitoring circuit can incorporate a bandgap circuit and can be used to control the input voltage based on the comparison of the supply voltage and a corresponding supply voltage threshold. The second monitoring circuit can incorporate a diode and can be used when the supply voltage is lower than a threshold voltage for the bandgap circuit. The second monitoring circuit can be used to control the input voltage based on a comparison of the supply voltage and a threshold voltage for the diode.