The ATA6405 is a fully integrated system voltage supply IC. The device is designed for the 12/24 V board voltage system in a motor vehicle. In order to minimize power consumption, a switching regulator generates a voltage for supplying the internal linear regulator with a 5 V output voltage for microcontrollers. To monitor the microcontroller, provision has been made for a window watchdog feature incorporating a reset logic function. The voltage system IC has three modes: active, Standby and OFF. One control input serves to facilitate the selection between the active and Standby modes. Another input permits the selection between the Standby and OFF modes. In the OFF mode, a maximum quiescent current of less than 10 A flows through the system and in Standby mode quiescent current less than 30 A.