4.39 V threshold, active-low open-drain reset for processor supervision
The MAX6315US44D1+ is a simple reset/power-on reset IC from Maxim Integrated, monitoring a single voltage rail at a 4.39 V threshold. When the monitored supply drops below that threshold, the open-drain output pulls low and holds the reset state for a minimum of 1 ms after the rail recovers — long enough for most MCUs and SoCs to complete their internal boot sequence before the core is released. A microcontroller in an outdoor telecom cabinet or a motor-drive control board that sees 105°C on a summer afternoon still has margin before the supervisor's own temperature derating becomes a concern.
SOT-23-4 package and surface-mount board integration
The four-pin footprint — VCC, GND, RESET, and a no-connect — keeps routing simple on a two-layer board; the open-drain output requires a pull-up resistor to the logic supply of the supervised device. If a board already carries a SOT-23-4 supervisor from this series, the layout is directly compatible.