TPS3618-50,pdf(Battery-Backup

The TPS3617 and TPS3618 are battery-backup supervisors that monitor 5 V supplies. They provide a battery-backup function ideal for applications that require data retention of CMOS RAM during fault conditions. When the voltage at V_DD drops below a preset threshold (V_IT), the active low push-pull RESET output asserts, and V_OUT switches from V_DD to V_BAT. When V_DD rises above the trip threshold, V_OUT switches immediately from V_BAT to V_DD. The RESET output remains low until the delay time (t_d) expires. During power on, RESET is asserted when the supply voltage (V_DD or V_BAT) goes higher than 1.1 V.

The PFI and PFO pins are provided if additional voltage monitoring is needed. If the voltage at PFI is less than 1.15 V, the push-pull PFO pin will assert low.