What the 4.38V threshold and second adjustable channel mean for your rail monitoring
The MAX6389XS44D3+T monitors two supply rails: one fixed at 4.38V and a second adjustable channel that lets you set the threshold with an external resistor divider — useful for tracking a 3.3V, 2.5V, or 1.8V core rail alongside the main 5V or 3.3V bus. The 140ms minimum reset timeout gives downstream logic time to stabilize after the rails come up, covering most processor and FPGA power-on reset requirements without an external delay capacitor. Active-low open-drain output lets you wire-OR the reset signal with other supervisors or a manual reset button — the pull-up resistor goes to the monitored rail or the I/O voltage, whichever the downstream device needs.
Temperature range and package — fits industrial and under-hood designs
Housed in the 4-pin SC-70-4 (SOT-343), it fits tight mixed-signal boards where every mm² counts — the 0.65mm lead pitch is hand-solderable with a fine-tip iron, so you can swap it in the field without a hot-air station.
Lifecycle and supply posture
RoHS3 compliant and supplied in tape-and-reel or cut-tape options, so it slots into both high-volume reflow and prototype builds without a process change.