Dual-rail supervisor with fixed thresholds
The TPS3306-33D is a multi-voltage supervisor from Texas Instruments that monitors two independent supply rails. The voltage thresholds are fixed at 2.93V and 4.55V, covering common 3.3V and 5V logic supplies. When either monitored voltage drops below its threshold, the open-drain output asserts a reset signal that stays active low for a minimum of 70ms after both rails recover. This timeout ensures the downstream processor or FPGA sees a clean power-good sequence.