Supervisor IC with battery backup for 3.3V rails
The TPS3619-33DGKRG4 is a battery backup supervisor from Texas Instruments that monitors a single 3.3V supply rail and switches to a backup battery when the main rail drops below the 2.93V threshold. Its active-low, push-pull reset output holds the system in reset for a minimum of 60ms after the supply returns, giving the processor time to stabilise before code execution starts. The battery backup circuit maintains the supply to SRAM or RTC registers during a power failure, preventing data loss without external sequencing logic.
2.93V threshold — where it trips
The 2.93V threshold is set for a nominal 3.3V rail. If your system uses a 3.0V or 3.6V supply, this part will either hold reset too aggressively or not trip early enough. The single-voltage monitor covers one rail; designs with multiple supplies need a multi-channel supervisor.
Housed in an 8-VSSOP package (3.00mm width), the part is a surface-mount fit for compact PCBs.