The Intersil X45620 combines power-on reset control, battery switch circuit, watchdog timer, supply voltage supervision, secondary voltage supervision, block lock protect and serial EEPROM in one package. This combination lowers system cost, reduces board space requirements, and increases reliability. Applying power to the device activates the power-on reset circuit which holds RESET active for a period of time. This allows the power supply and oscillator to stabilize before the processor can execute code. A system battery switch circuit compares VCC (V1MON) with VBATT input and connects VOUT to whichever is higher. This provides voltage to external SRAM or other circuits in the event of main power failure. The X45620 can drive 50mA from VCC and 250A from VBATT. The device switches to VBATT when VCC drops below the low VCC voltage threshold and VBATT > VCC.