What the 3V threshold and 619 ms timeout mean for your ECU
The TPS3840PL30DBVRQ1 is a Texas Instruments automotive-grade simple reset IC, AEC-Q100 qualified, monitoring a single 3V rail with an active-low, push-pull output. The 3V threshold is set for 3.3V logic supplies — when the rail dips below 3V, the output pulls low and holds the microcontroller in reset for a typical 619 ms after the rail recovers. That 619 ms window is long enough for a bulk capacitor on the 3.3V rail to charge past the threshold before the CPU starts executing, which avoids the classic power-up brown-out glitch that corrupts flash vectors.
Temperature range and package — board-fit check
The SOT-23-5 package is a 5-lead SC-74A variant with 0.95 mm pitch — a straightforward two-layer board can route it, but keep the reset output trace short to avoid coupling noise back into the sense input.
It is ROHS3 compliant. No stock-holding claim; quoted per RFQ.