Four-rail voltage watchdog in a 4x4 mm QFN
The MAX16008TP+T: It monitors up to four supply rails simultaneously and asserts an active-low, open-drain reset output when any monitored voltage falls below its threshold. The reset timeout is under 1 ms minimum, which means the downstream processor sees a clean reset pulse even on fast supply droops — useful for catching brownout conditions that a longer timeout might miss.
Four independent voltage monitors let this single IC replace four separate supervisor devices on a multi-rail board — a space and BOM-line saving for systems with separate core, I/O, memory, and auxiliary supplies. The -40°C to +125°C operating range covers industrial and automotive ambient conditions, so the supervisor stays reliable in an engine bay or a factory floor enclosure without a separate temperature-grade variant. Voltage thresholds are adjustable via external resistor dividers, giving the designer flexibility to set trip points for non-standard rails without changing the IC order code.
The 20-WFQFN exposed-pad package (4x4 mm) requires a thermal via array under the paddle to achieve the rated power dissipation — the datasheet layout recommendation should be followed for reliable operation at the high end of the temperature range. Surface-mount assembly with the exposed pad soldered to the PCB ground plane also provides a low-inductance return path for the open-drain output, keeping the reset signal clean during transient events.