4.1V threshold supervisor in a 1.5x1.5 mm WSON
The reset output remains asserted for a typical 40µs timeout after the rail recovers, providing a clean power-on reset signal to the downstream MCU, FPGA, or SoC. Housed in a 6-WSON (1.5x1.5) package, it is suited for space-constrained boards in industrial control, automotive electronics, and portable equipment where the supervisor must fit near the monitored rail without consuming much board area.
The open-drain output and active-low reset are standard across the TPS3899 family, so the base product number TPS3899 offers multiple threshold options if the 4.1V point is not the exact fit.
40µs timeout and open-drain output — what they mean on the board
The 40µs typical reset timeout is short enough that the downstream processor starts code execution quickly after the supply stabilises, but long enough to filter out brief supply glitches that could cause a spurious reset. The open-drain output lets the supervisor share a reset line with other devices (like a watchdog or manual reset button) through a pull-up resistor to the core voltage rail. The active-low polarity is the convention for most MCU reset inputs, so no inversion logic is needed. The 6-WSON package with a 1.5x1.5 mm footprint fits under a small decoupling cap or near the power-entry connector, keeping the reset trace short.
Surface-mount assembly with the 6-WFDFN package uses standard reflow profiles; the small pad area means the thermal dissipation is minimal, so no special via stitching is needed for this low-power device.