Dual-rail supervisor for mixed-voltage systems
The Texas Instruments TPS3305-18DGN is a multi-voltage supervisor that monitors two supply rails simultaneously — one at 1.68V and the other at 2.93V — and asserts a reset when either rail drops below its threshold. It provides both active-high and active-low reset outputs in a push-pull, totem-pole configuration, giving the designer flexibility to interface with processor reset inputs that expect either polarity.
Threshold selection and rail compatibility
The 1.68V threshold is sized for 1.8V logic rails — typical of DDR memory or low-voltage I/O banks — while the 2.93V threshold covers 3.0V or 3.3V supplies with enough margin to catch a brownout before the downstream logic fails. Monitoring two voltages in one package saves board space and reduces component count compared to using two single-channel supervisors, which matters in dense designs like base stations or industrial controllers.