2.19V threshold — the trip point that matters
The MAX6381XR22D3+ is a single-voltage power-supply monitor from Analog Devices, part of the MAX6381 family. Its job is to hold a microprocessor or logic device in reset until the supply rail is stable, and to assert reset again if the rail dips below the threshold. That 2.19 V figure is the one you match against the minimum operating voltage of the downstream device — pick a threshold above the processor's brownout floor, not below it. The reset timeout is 140 ms minimum, giving the supply and oscillator time to settle before the processor starts executing code.
Temperature grade and deployment context
The package is SC-70-3 (SOT-323), a 3-lead surface-mount footprint that fits tight layouts. The supplier device package is SC-70-3, so the PCB land pattern is standard for that outline — no special footprint work needed.