The SGM811/SGM812 supervisory circuits monitor the power supply voltage in microprocessor and digital systems. The SGM811/SGM812 are designed to monitor eight different voltages; these voltages have been selected for the effective monitoring of 1.8V, 2.5V, 3V, 3.3V and 5V supply voltage levels.

They provide a reset output during power-up, power-down and brownout conditions. On power-up, an internal timer holds reset asserted for 240ms. This holds the microprocessor in a reset state until conditions have stabilized. The nRESET output remains operational with V_CC as low as 1V. The SGM811 provides an active low reset signal (nRESET) while the SGM812 provides an active high signal (RESET) output.

Included in this circuit is a manual reset input. The manual reset function is very useful, especially if the circuit in which the SGM811/SGM812 is operating enters into a state that can only be detected by the user. Allowing the user to reset a system manually can reduce the damage or danger that could otherwise be caused by an out-of-control or locked system. The devices come in SOT-143 and SOT-23-5 packages.