What this supervisor does on your rail
The TPS3839L30DQNR is a Texas Instruments Simple Reset/Power-On Reset IC that monitors a single supply rail and asserts a reset signal when the voltage drops below 2.63V threshold. The output is Active Low, push-pull, totem pole — it pulls low on fault and drives high when the supply is valid, no external pull-up needed. The 120ms minimum reset timeout holds the system in reset long enough for the supply to stabilise after a brown-out or power-up, preventing premature processor start-up that could cause code corruption.
Threshold and timeout — sizing for your rail
With a 2.63V threshold, this part is designed to supervise a 2.5V or 3.0V nominal supply rail — the reset asserts when the rail falls to 2.63V, which is typically 88% of 3.0V or 105% of 2.5V. For a 3.3V rail, the TPS3839L33DQNR variant with a higher threshold is the correct fit. The 120ms minimum reset timeout is fixed and non-adjustable — it suits most MCU boot sequences that need 50-100 ms of stable supply before release. If your system needs a longer delay, a supervisor with a programmable timeout or a larger capacitor on the delay pin would be required.
It is ROHS3 compliant. The 4-X2SON (1x1) package is a small footprint that may require a specific stencil aperture for reliable solder paste deposition; confirm your assembly house can handle 1x1 mm packages before committing.
Housed in a 4-X2SON (1x1) package — 1 mm x 1 mm, 4 leads, with an exposed pad for thermal dissipation.