Analog Devices Inc./Maxim Integrated MAX6831SZUT

Overview

The MAX6831SZUT from Maxim Integrated is an ultra-low-voltage dual microprocessor supervisory circuit in SOT23-6 package, designed to monitor primary supply (VCC) and secondary supply (VCC2) with factory-trimmed thresholds, manual reset input (MR), and watchdog timer (WDI). It asserts open-drain RESET during VCC/VCC2 undervoltage, MR assertion, or watchdog timeout, with 140ms minimum reset timeout and guaranteed operation down to VCC = +1.0V. Used in battery-powered embedded controllers requiring reliable brownout protection.

For engineers reviewing the MAX6831SZUT datasheet, MAX6831SZUT pinout, MAX6831SZUT application, or MAX6831SZUT equivalent, this page delivers verified functional identity, exact reset threshold values (VCC = 1.575V ±0.05V, VCC2 = 1.575V ±0.05V), open-drain output behavior, watchdog timeout (1.6s nominal), and validated alternative options for dual-supply µP supervision.

Technical Context

The MAX6831SZUT integrates two independent voltage comparators-one for VCC (threshold suffix V = 1.575V) and one factory-trimmed for VCC2 (also 1.575V)-feeding into a logic OR gate that triggers reset assertion. Its open-drain RESET output requires external pull-up and supports bidirectional µP reset I/O interfaces like Motorola 68HC11.

It features a 1.6s watchdog timer cleared by WDI edges or reset assertion, and a manual reset input (MR) with internal 50kΩ pull-up. Reset remains active for ≥140ms after all monitored voltages recover, ensuring stable processor initialization during power transients.

Key Specifications

Pinout & Package

Package: 6-pin SOT23-6, surface-mount, lead-free compatible (UT-T suffix denotes RoHS-compliant packaging).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-supply microprocessor supervision applications.

Compared with MAX6829SZUT, MAX6831SZUT provides essential open-drain flexibility for bidirectional reset interfaces, while TPS3808G15DBVR reduces feature set and package count but sacrifices dual-supply coverage and watchdog safety-making MAX6831SZUT the sole option when both VCC2 monitoring and WDI-based firmware supervision are mandatory.

Availability

MAX6831SZUT is available at Aetrix Electronics and suitable for portable medical sensors, automotive body control modules, industrial PLC I/O submodules, smart energy meters, and critical µP monitoring applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6831SZUT includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power management ICs for demanding industrial, automotive, and computing applications.

The MAX6826–MAX6831 family was engineered specifically for ultra-low-voltage dual-rail microprocessor supervision in space-constrained, battery-operated systems-emphasizing guaranteed operation down to VCC = +1.0V and factory-trimmed secondary thresholds.

FAQ

What is the exact VCC reset threshold voltage for MAX6831SZUT?

The MAX6831SZUT has a VCC reset threshold of 1.575V, with guaranteed min/max values of 1.521V and 1.629V across the full -40°C to +125°C operating temperature range. This value corresponds to the 'V' suffix in the part number and is factory-trimmed for high accuracy without external components. The MAX6831SZUT uses this threshold to monitor the primary supply and initiate reset when VCC falls below it.

Does MAX6831SZUT support monitoring of a secondary voltage, and what is its threshold?

Yes, the MAX6831SZUT monitors a secondary voltage via the VCC2 pin with a factory-trimmed threshold of 1.575V (same tolerance: 1.521V to 1.629V over temperature). Unlike the adjustable RESET IN input found on MAX6826–MAX6828, VCC2 is fixed and optimized for +0.9V to +2.5V supplies. This dual-monitoring capability is integral to the MAX6831SZUT's role in multivoltage systems.

What type of RESET output does MAX6831SZUT provide, and how should it be interfaced?

The MAX6831SZUT provides an active-low open-drain RESET output (Pin 1), requiring an external pull-up resistor to the appropriate logic rail (e.g., 3.3V or 5V). This configuration allows safe wired-OR connection and direct interfacing with microprocessors featuring bidirectional reset I/O, such as the Motorola 68HC11. The MAX6831SZUT's open-drain architecture prevents bus contention and simplifies multi-supervisor designs.

What is the watchdog timeout period for MAX6831SZUT, and how is it cleared?

The MAX6831SZUT features a nominal 1.6s watchdog timeout period (ranging from 0.80s to 2.60s over temperature), which is cleared by any rising or falling edge on the WDI pin (Pin 4), or automatically upon reset assertion. The internal timer restarts immediately after reset release. This behavior enables robust firmware hang detection in the MAX6831SZUT, making it suitable for safety-critical embedded applications where software liveness must be verified.

Is MAX6831SZUT guaranteed to operate correctly at very low VCC levels?

Yes, the MAX6831SZUT is explicitly guaranteed to assert a valid reset signal down to VCC = +1.0V, ensuring deterministic behavior during deep brownout conditions common in battery-powered systems nearing end-of-discharge. This specification is validated across the full -40°C to +125°C temperature range and is a key differentiator of the MAX6831SZUT versus generic supervisors with higher minimum operating voltages.