Two-channel supervisor for multi-rail sequencing
The TPS3421ECDRYT is a Reset Timer supervisor from Texas Instruments that monitors two supply voltages and asserts an active-low reset signal when either rail falls below the adjustable threshold. The open-drain output holds the reset for a minimum of 64 ms after all monitored voltages return to tolerance, giving the downstream processor time to stabilize before release. The 6-SON package (1.45 mm x 1 mm) fits tight layouts on multi-layer boards.
Reset timeout and threshold flexibility
The 64 ms minimum reset timeout is long enough to cover most processor boot sequences and power-good settling times. The voltage threshold is adjustable via external resistors, so the same part can be used across 1.8 V, 2.5 V, 3.3 V, or other rails without changing the order code. Active-low reset with open-drain output allows wired-OR connection with other supervisors or manual reset buttons. The output pulls low when either monitored voltage drops below the threshold and stays low for the full timeout after recovery.
The 6-SON (1.45 mm x 1 mm) package has a 0.50 mm pitch and an exposed thermal pad on the bottom.