Analog Devices Inc./Maxim Integrated MAX6831TZUT

Overview

MAX6831TZUT from Maxim Integrated is an ultra-low-voltage dual microprocessor supervisory circuit in SOT23-6 package, monitoring primary supply (VCC) and secondary supply (VCC2) with factory-trimmed 1.575V reset threshold for VCC and 0.788V for VCC2, featuring open-drain active-low RESET output, manual reset input (MR), and 1.6s watchdog timeout - used in battery-powered embedded controllers requiring reliable brownout and watchdog protection.

For engineers reviewing the MAX6831TZUT datasheet, MAX6831TZUT pinout, MAX6831TZUT application, or MAX6831TZUT equivalent, this page delivers verified electrical parameters, exact pin functions, real-world timing behavior (140ms min reset timeout, 1.6s watchdog period), and validated alternative parts for multivoltage system design and µP reset integrity assurance.

Technical Context

The MAX6831TZUT implements dual independent voltage monitoring: VCC monitored against a fixed 1.575V threshold (±3% over –40°C to +125°C), and VCC2 against a fixed 0.788V threshold (±3%), both with 60ppm/°C temperature coefficient and 2×VTH hysteresis. It uses internal BiCMOS technology with 750 transistors to guarantee valid reset assertion down to VCC = +1.0V.

Its open-drain RESET output supports bidirectional µP reset I/O (e.g., Motorola 68HC11), while MR features a 50kΩ internal pullup and 200ns response delay, and WDI detects edges ≥50ns to clear the 1.6s watchdog timer - all without external components.

Key Specifications

Pinout & Package

MAX6831TZUT is housed in a lead-free 6-pin SOT23-6 package (2.9mm × 1.6mm × 1.1mm), compatible with standard reflow profiles and space-constrained PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6831TZUT, MAX6829TZUT offers stronger RESET drive but sacrifices bidirectional compatibility, while TPS3808G15DBVR reduces feature set and monitoring capability - making MAX6831TZUT the optimal choice for compact dual-rail systems needing watchdog and flexible reset signaling.

Availability

MAX6831TZUT is available at Aetrix Electronics and suitable for portable/battery-powered equipment, embedded controllers, and intelligent instruments requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6831TZUT 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 demanding industrial, automotive, and communications applications - emphasizing high reliability, low power, and small form factor.

The MAX6826–MAX6831 family was engineered specifically for multivoltage µP systems where simultaneous monitoring of primary and secondary rails, manual reset, and watchdog functionality must coexist in minimal PCB area - targeting portable, automotive, and instrumentation markets.

FAQ

What is the exact VCC2 reset threshold voltage for MAX6831TZUT?

The MAX6831TZUT has a factory-trimmed VCC2 reset threshold of 0.788V ±3% over –40°C to +125°C, as specified in the Threshold Suffix Guide for suffix 'T' (VCC = 1.575V) and 'Z' (VCC2 = 0.788V). This value is measured at the VCC2 pin and is guaranteed across temperature and process variation - no external calibration is needed. The MAX6831TZUT uses this fixed threshold to supervise low-voltage core supplies such as 0.9V rails.

Does MAX6831TZUT support bidirectional µP reset pins?

Yes, the MAX6831TZUT supports bidirectional µP reset pins via its open-drain active-low RESET output. When connected with a single external pullup resistor to VCC, it can both assert reset (by pulling low) and release reset (allowing pullup to drive high), matching the behavior required by µPs like the Motorola 68HC11. This eliminates level shifters or additional logic - a key advantage over push-pull alternatives like MAX6829TZUT. The MAX6831TZUT's open-drain architecture is explicitly designed for this use case.

What is the minimum VCC voltage at which MAX6831TZUT guarantees valid reset operation?

The MAX6831TZUT guarantees valid reset assertion and timing behavior down to VCC = +1.0V, as confirmed in the Absolute Maximum Ratings and Electrical Characteristics tables. This means the internal comparators, timer, and RESET driver remain fully functional and meet all specified thresholds and delays even as the supply drops to 1.0V - critical for detecting deep brownout conditions before system failure. Below 1.0V, reset behavior is not guaranteed, and the MAX6831TZUT may cease operation.

How does the watchdog timer in MAX6831TZUT respond to WDI signal transitions?

The MAX6831TZUT watchdog timer clears on any rising or falling edge at the WDI pin with pulse width ≥50ns. If WDI remains static (high or low) for longer than the 1.6s timeout period, a reset is asserted for the full 140ms reset timeout. The timer also clears automatically during active reset or manual reset assertion. Leaving WDI unconnected disables the watchdog, as the internal driver toggles it every ~1.4s - a behavior documented in the Applications Information section of the MAX6831TZUT datasheet.

Can MAX6831TZUT monitor a 1.2V supply as VCC2?

No, the MAX6831TZUT is factory-trimmed for a fixed VCC2 threshold of 0.788V and cannot monitor a 1.2V supply directly on the VCC2 pin. Attempting to apply 1.2V to VCC2 would exceed the absolute maximum rating of +2.5V but more critically would not trigger reset at the intended trip point. For 1.2V supervision, use the RESET IN input (on MAX6826–MAX6828 variants) with an external resistor divider - however, the MAX6831TZUT lacks RESET IN; it only supports VCC2 monitoring at its fixed 0.788V threshold.