Voltage monitoring requirements vary depending on the voltage supply tolerance of the device being powered. Because of the high precision of the TPS3704-Q1 (±1% max), the device allows for wider supply voltage margins and threshold headroom for tight tolerance applications.

For example, take a DC/DC regulator providing power to a core voltage rail of a microcontroller (MCU). The MCU has a tolerance of ±5% of the nominal output voltage of the DC/DC. The user sets an ideal voltage threshold of ±4%, which allows for ±1% of threshold accuracy. Because the TPS3704-Q1 threshold accuracy is ±1%, the user has more supply voltage margin, which can allow for a relaxed power supply design. This design gives flexibility to the DC/DC to use a smaller output capacitor or inductor because of a larger voltage window for voltage ripple and transients. There is also headroom between the minimum system voltage and voltage tolerance of the MCU to make sure that the voltage supply is never in the region of potential failure of malfunction without the TPS3704-Q1 asserting a reset signal.

Figure 8-1 shows the supply undervoltage margin and accuracy of the TPS3704-Q1 for the example explained in this section. Using a low accuracy supervisor cuts into the available budget for the power-supply ripple and transient response. This gives less flexibility to the user and a more stringent DC/DC converter design.

Figure 8-1 TPS3704-Q1Voltage Threshold Accuracy