Analog Devices Inc./Maxim Integrated MAX6831SDUT

Overview

MAX6831SDUT from Maxim Integrated is an ultra-low-voltage dual microprocessor supervisory circuit in SOT23-6 package, monitoring primary supply (VCC) at 1.575V threshold and secondary supply (VCC2) at 0.788V threshold, with open-drain active-low RESET output, manual reset input (MR), and 1.6s watchdog timeout - used in battery-powered embedded systems to ensure reliable power-on reset and brownout recovery.

For engineers reviewing the MAX6831SDUT datasheet, MAX6831SDUT pinout, MAX6831SDUT application, or MAX6831SDUT equivalent, key selection considerations include its factory-trimmed dual-supply monitoring capability, guaranteed reset validity down to VCC = +1.0V, open-drain RESET compatibility with bidirectional µP reset pins, and immunity to short negative VCC transients.

Technical Context

The MAX6831SDUT integrates two independent voltage comparators: one for primary VCC (threshold = 1.575V ±25mV over –40°C to +125°C) and one factory-trimmed comparator for VCC2 (threshold = 0.788V ±25mV). Its internal 140ms minimum reset timeout delay generator ensures stable deassertion after supply recovery.

It features a dedicated WDI input with 50ns pulse detection, internal 50kΩ MR pullup, and open-drain RESET output capable of sinking ≥50µA at VCC ≥ 1.0V. The device operates across full industrial temperature range (–40°C to +125°C) with supply current as low as 2µA (VCC2 ≤ +2.5V) and 30µA (VCC = +1.53V to +2.0V).

Key Specifications

Pinout & Package

SOT23-6 package: 2.9mm × 1.6mm × 1.1mm body, gull-wing leads, moisture sensitivity level 1, RoHS-compliant lead-free option available (+T suffix).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6829SDUT, MAX6831SDUT's open-drain RESET enables flexible bus interfacing but requires external pullup; compared with TPS3808G15DBVR, it adds critical dual-rail monitoring and watchdog safety for complex embedded systems.

Availability

MAX6831SDUT is available at Aetrix Electronics and suitable for battery-powered portable equipment, automotive body control modules, and industrial sensor nodes requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6831SDUT 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 and mixed-signal ICs for power, sensing, and connectivity applications in industrial, automotive, and medical markets.

The MAX6826–MAX6831 family delivers ultra-low-voltage dual-supply supervision with integrated watchdog and manual reset - engineered specifically for reliability-critical embedded systems operating from single-cell batteries or multi-rail power architectures.

FAQ

What is the exact VCC2 reset threshold voltage for MAX6831SDUT?

The MAX6831SDUT has a factory-trimmed VCC2 reset threshold of 0.788V (minimum 0.761V, maximum 0.815V) over the full –40°C to +125°C temperature range. This value is fixed per the "D" suffix in the part number and does not require external resistor programming - unlike the adjustable RESET IN input found on MAX6826/MAX6827/MAX6828 variants. The MAX6831SDUT uses this precise threshold to supervise low-voltage rails such as 0.9V or 1.2V cores without calibration.

Does MAX6831SDUT support watchdog functionality, and what is its timeout period?

Yes, MAX6831SDUT includes a fully functional watchdog timer with a nominal timeout period of 1.6 seconds. The watchdog triggers a reset if the WDI pin remains static (high or low) beyond this interval. The timer clears on any rising or falling edge at WDI, on MR assertion, or during active RESET. The MAX6831SDUT guarantees detection of pulses as short as 50ns on WDI, making it suitable for high-speed firmware heartbeat signaling in real-time embedded applications.

What is the RESET output configuration of MAX6831SDUT, and how should it be interfaced?

The MAX6831SDUT features an open-drain active-low RESET output (Pin 1), requiring an external pullup resistor to VCC or another logic rail. This configuration allows wired-OR connection with other reset sources and direct interfacing to microcontrollers with bidirectional reset I/O (e.g., Motorola 68HC11). The MAX6831SDUT's RESET can sink ≥50µA at VCC ≥ 1.0V, supporting standard 10kΩ pullups while maintaining fast rise/fall times in noise-sensitive environments.

Can MAX6831SDUT monitor a 1.8V supply as VCC2?

No - the MAX6831SDUT's VCC2 input is factory-trimmed to 0.788V and is intended for monitoring sub-1V rails such as 0.9V or 1.2V cores. A 1.8V supply applied to VCC2 would exceed the absolute maximum rating of +2.5V for that pin and risk damage. For 1.8V supervision, use the primary VCC input (threshold 1.575V) or select a different variant like MAX6830SDUT with higher VCC2 threshold options (e.g., "Y" = 2.188V). The MAX6831SDUT is optimized for ultra-low-voltage dual-rail systems, not mid-range supplies.

What is the minimum VCC voltage at which MAX6831SDUT guarantees correct reset behavior?

The MAX6831SDUT guarantees correct reset assertion and deassertion down to VCC = +1.0V across the full –40°C to +125°C operating temperature range. Below this voltage, the internal comparators and logic may become indeterminate. This specification ensures reliable brownout detection even during severe battery discharge or LDO dropout conditions. The MAX6831SDUT's design maintains valid reset state integrity at voltages where many competing supervisors fail - a key requirement for energy-harvesting and ultra-low-power IoT endpoints.