Two-rail supervisor in an SOIC-8 footprint
The Texas Instruments TPS3305-18DRG4 is a multi-voltage supervisor that monitors two supply rails with thresholds at 1.68 V and 2.93 V, generating a push-pull reset output that is both active high and active low. The 140 ms minimum reset timeout holds downstream logic in reset long enough for the core supply to stabilise after power-up or a brown-out event.
Thresholds and reset behaviour for mixed-voltage boards
The 1.68 V threshold suits a 1.8 V core rail — the supervisor asserts reset when that rail drops below the threshold, protecting the logic from undefined states. The 2.93 V threshold covers a 3.3 V I/O or memory rail, so a single TPS3305-18DRG4 replaces two separate supervisor ICs in a dual-voltage system. Both active-high and active-low outputs are available from the same device, giving the designer flexibility to drive reset inputs of opposite polarity without an inverter.
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