Supervisor for 5V rails — 4.6V threshold and 619 ms timeout
The TPS3840DL46DBVR is a single-channel voltage supervisor from Texas Instruments, designed to hold a microcontroller or FPGA in reset until the supply rail stabilises. Its 4.6V threshold is a natural fit for monitoring a nominal 5V rail, asserting reset when the voltage dips below that level. The reset output is active-low, open-drain, so it can be wire-ORed with other reset sources or pulled up to any logic voltage up to the absolute maximum rating — no level-shifting needed when interfacing to 3.3V or 1.8V logic. A built-in 619 ms (typical) reset timeout keeps the system in reset long enough for the supply to ring up cleanly after a brownout, without requiring an external capacitor.
Temperature range and package for industrial builds
The 5-pin footprint breaks out to the supply rail, ground, reset output, and a manual-reset input on the base part — though this variant is a dedicated supervisor without MR.
Sourcing posture — active, single-source, no direct replacement
There is no official pin-compatible second source from another manufacturer. Within the TPS3840 family, other threshold voltages (e.g. 3.0V, 3.3V, 5.0V) share the same SOT-23-5 footprint but differ in trip point — confirm the rail voltage before substituting.