What this supervisor does on your board
The Maxim DS1231S-20+ is a Simple Reset/Power-On Reset supervisor that monitors a single voltage rail and holds the system in reset until the supply stabilizes. It asserts both active-high and active-low reset signals through an open-drain output, giving you flexibility to drive either polarity of the processor reset pin.
Package and temperature — board-fit check
Housed in a 16-SOIC wide-body package (7.50 mm body width), surface-mount only. Not rated for industrial enclosures, motor drives, or outdoor telecom where the ambient might dip below freezing or climb above 70°C.
ROHS3 compliant. For BOM freeze or second-source planning, there is no official cross-reference — this is a Maxim-specific part, and a direct pin-compatible alternate would need to be validated against the same threshold and timeout specs.