1.52 V threshold supervisor for tight low-voltage rails
The TPS3839E16DQNR is a single-channel voltage supervisor from TI that holds a processor in reset until the monitored supply crosses 1.52 V and stays there for at least 120 ms. It targets 1.8 V nominal rails — common in low-power MCUs, FPGAs, and DSP cores — where a clean power-on sequence is critical to avoid latch-up or undefined boot states.
The 1.52 V threshold sits about 84 % of a nominal 1.8 V rail. With a ±5 % supply tolerance the rail bottoms at 1.71 V, so this part doesn't nuisance-trip on normal ripple. It catches genuine brownouts below 1.52 V — the sort of sag you see when a peripheral powers up and drags the core rail down. For a 16 MHz MCU that's about 1.9 million clock cycles of guaranteed hold-off.
X2SON-4: tiny footprint, tight layout rules
The 1x1 mm X2SON package (supplier device package 4-X2SON) is roughly the area of an 0402 resistor. A fine-pitch stencil (0.1 mm thick or less) and a reflow profile matched to the small thermal mass are needed to avoid tombstoning or insufficient solder joint height. The package is rated for surface-mount assembly only.
TI lists the TPS3839E16DQNR as Active. The base product number TPS3839 covers multiple threshold options (1.52 V, 1.8 V, 2.5 V, etc.) sharing the same package and pinout, so if the 1.52 V variant ever phases out, a threshold-adjacent sibling is a plausible drop-in — but no official successor has been declared. For now, this part is fully in production and sourced through standard distribution.