The DS1836 MicroManager performs three vital system functions. First, a precision temperaturecompensated reference and comparator circuit monitor the status of the voltage on VCC and when an outof-tolerance condition is detected, an internal power-fail signal is generated that forces the reset active. If VCC continues to degrade, it switches to the battery supply when VCC drops below 3.8V (2.6V for 3.3V versions). When VCC exceeds 3.9V (2.8V for 3.3V versions); VOUT will again be supplied from VCC. Reset will remain active for 350 ms after VCC returns to an in-tolerance condition. Lastly, the DS1836 supports a sense input that sends a non-maskable interrupt whenever the sense input drops below 1.25V.