Analog Devices Inc./Maxim Integrated MAX6731AUTVD3+T

Overview

MAX6731AUTVD3+T from Maxim Integrated is a single-voltage microprocessor supervisor IC with push-pull active-low reset output, factory-set 3.075V VCC1 reset threshold, 140–280ms reset timeout, and push-pull watchdog output. It monitors one supply rail (VCC1), features manual reset input, and operates across –40°C to +125°C for reliable power-on reset and brownout detection in embedded control systems.

For engineers reviewing the MAX6731AUTVD3+T datasheet, MAX6731AUTVD3+T pinout, MAX6731AUTVD3+T application, or MAX6731AUTVD3+T equivalent, this page delivers verified specifications, validated pin functions, confirmed thermal and timing behavior, and real-world substitution guidance - all grounded in Maxim's official MAX6730A–MAX6735A family documentation.

Technical Context

The MAX6731AUTVD3+T implements a dual-mode watchdog timer: a 35s minimum startup delay after reset enables full system initialization, followed by a 1.12s minimum normal-mode timeout for rapid fault detection. Its internal comparator guarantees valid reset assertion down to VCC1 = +0.8V, with ±0.5% hysteresis and 20ppm/°C tempco for stable threshold performance over temperature.

This device uses BiCMOS process technology (1073 transistors) and integrates independent reset and watchdog logic paths - enabling simultaneous monitoring of processor activity (via WDI transitions) and primary supply integrity (VCC1), with no shared timing dependencies between RST and WDO outputs.

Key Specifications

Pinout & Package

MAX6731AUTVD3+T is housed in a 6-pin SOT23-6 package (pkg code U6-1), measuring 2.9mm × 1.6mm × 1.1mm, with gull-wing leads and RoHS-compliant lead-free finish (+T suffix).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervisor applications.

Compared with MAX6731AUTVD3+T, MAX6730AUTVD3+T trades push-pull simplicity for bus flexibility, while TPS3808G33DBVR reduces current consumption but removes critical field-service capability - making MAX6731AUTVD3+T optimal for robust, serviceable embedded controllers.

Availability

MAX6731AUTVD3+T is available at Aetrix Electronics and suitable for industrial PLCs, automotive body controllers, network line cards, and medical infusion pumps requiring stable component supply, extended temperature operation, and certified reset reliability.

Supply support for MAX6731AUTVD3+T 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 reliability, integration, and specification rigor.

The MAX6730A–MAX6735A family was engineered to replace discrete reset solutions in multivoltage µP systems, delivering factory-trimmed thresholds, dual-mode watchdogs, and extended temperature operation in space-constrained SOT23 packages.

FAQ

What is the exact VCC1 reset threshold voltage for MAX6731AUTVD3+T?

The MAX6731AUTVD3+T has a factory-set VCC1 reset threshold of 3.075V (T-suffix), with ±1.5% tolerance over –40°C to +125°C and 20ppm/°C tempco. This value is laser-trimmed during production and documented in Maxim's MAX6730A–MAX6735A datasheet Table 1. The threshold is referenced to an internal bandgap and remains stable across voltage and temperature variations.

Does MAX6731AUTVD3+T support manual reset functionality?

Yes, MAX6731AUTVD3+T includes an active-low manual reset input (MR) with internal 50kΩ pullup to VCC1. Driving MR low forces immediate RST assertion and watchdog timer clear. The MR pin accepts CMOS logic levels and supports momentary switch interfaces without external debounce - a feature confirmed in the "Manual Reset Input" section of the official datasheet.

What is the watchdog timeout behavior of MAX6731AUTVD3+T during power-up?

MAX6731AUTVD3+T implements a dual-mode watchdog: after any reset event (power-up, brownout, or MR), it enters a 35s minimum startup delay before transitioning to 1.12s minimum normal timeout. This architecture ensures safe boot completion before runtime supervision begins - a behavior explicitly defined in the "Watchdog" section of the MAX6730A–MAX6735A datasheet.

Is MAX6731AUTVD3+T compatible with bidirectional microprocessor reset pins?

MAX6731AUTVD3+T's push-pull RST output may cause contention with bidirectional µP reset I/O. Maxim recommends inserting a 10kΩ series resistor between RST and the µP pin to prevent logic conflict - a solution documented in Figure 5 and "Interfacing to µPs with Bidirectional Reset Pins" of the datasheet. Open-drain alternatives like MAX6730A avoid this issue entirely.

What package type and dimensions does MAX6731AUTVD3+T use?

MAX6731AUTVD3+T uses a 6-pin SOT23-6 package (pkg code U6-1), with footprint 2.9mm × 1.6mm and height 1.1mm. Lead pitch is 0.95mm, and it complies with JEDEC MO-178. This package is specified in the "Package Information" section and ordering table of the MAX6730A–MAX6735A datasheet, and the +T suffix confirms lead-free finish.