What this supervisor does on the board
The Maxim Integrated DS1231-20+ is a simple reset/power-on reset supervisor IC that monitors a single voltage rail and asserts a reset signal when the supply drops below a programmed threshold. It provides both active-high and active-low reset outputs from an open-drain output stage, giving the designer flexibility to interface with either polarity of the system's reset input. The reset timeout is a minimum of 150 ms, which gives the main supply and oscillator time to stabilize before the processor starts executing code.
Thresholds and temperature — fit for your rail
This part monitors a single voltage with two internal thresholds: 4.37 V and 4.62 V. The dual-threshold scheme provides built-in hysteresis — the reset asserts at the lower threshold and de-asserts at the higher one, preventing chatter during a slowly rising supply. The operating temperature range is 0°C to 70°C, which suits indoor equipment, office electronics, and benchtop instruments but not outdoor or under-hood automotive environments.
Package and mounting
Housed in an 8-pin PDIP (0.300" wide, 7.62 mm pitch) with through-hole mounting, the DS1231-20+ is a straightforward part to hand-assemble or rework.
Sourcing and lifecycle
The DS1231-20+ carries an Active lifecycle status and is ROHS3 compliant.