The TL7770 is an integrated-circuit system supervisor designed for use as a reset controller in microcomputer and microprocessor power-supply systems. This device contains two independent supply-voltage supervisors that monitor the supplies for overvoltage and undervoltage conditions at the VSO and VSU terminals, respectively. When VCC attains the minimum voltage of 1 V during power up, the RESET output becomes active (low). As VCC approaches 3.5 V, the time-delay function activates, latching RESET and RESET active (high and low, respectively) for a time delay (td) after system voltages have achieved normal levels. Above VCC = 3.5 V, taking RESIN low activates the time-delay function during normal system-voltage levels. To ensure that the microcomputer system has reset, the outputs remain active until the voltage at VSU exceeds the threshold value, VIT+, for a time delay, which is determined by an external timing capacitor such that: td