Analog Devices Inc./Maxim Integrated MAX6731AUTRD3+T

Overview

MAX6731AUTRD3+T from Maxim Integrated is a single-voltage microprocessor supervisor IC with push-pull active-low reset output, manual reset input, and independent push-pull watchdog output. It monitors one fixed supply (VCC1) at +3.075V nominal threshold, provides 140ms–280ms reset timeout, operates from -40°C to +125°C, and draws only 14µA typical supply current at +3.6V - used in telecom power sequencing and industrial controller brownout protection.

For engineers reviewing the MAX6731AUTRD3+T datasheet, MAX6731AUTRD3+T pinout, MAX6731AUTRD3+T application, or MAX6731AUTRD3+T equivalent, key selection criteria include its factory-set VCC1 reset threshold (+3.075V), push-pull RST/WDO outputs eliminating external pullups, 54s initial watchdog startup delay for safe boot, and guaranteed reset validity down to VCC1 = +0.8V.

Technical Context

The MAX6731AUTRD3+T implements dual-mode watchdog timing: a 35s–72s initial timeout after reset enables full system initialization, followed by a 1.12s–2.24s normal-mode timeout for rapid fault detection. Its reset logic asserts RST low when VCC1 falls below +3.075V (±2.5% over temperature), MR is pulled low, or WDI stalls - with hysteresis of 0.5% and immunity to sub-100ns VCC transients.

It integrates a precision bandgap reference for threshold stability (20ppm/°C tempco), supports manual reset via internal 50kΩ pullup, and guarantees functional reset assertion even as VCC1 decays to +0.8V - critical for fail-safe shutdown in battery-backed systems and automotive ECUs.

Key Specifications

Pinout & Package

MAX6731AUTRD3+T is housed in a 6-pin SOT23-6 package (package 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 MAX6730AUTRD3+T and TPS3808G33DBVR, the MAX6731AUTRD3+T uniquely combines push-pull RST/WDO outputs, manual reset, and dual-mode watchdog in a 6-pin SOT23 - enabling simpler, more robust reset architecture without external components or secondary ICs.

Availability

MAX6731AUTRD3+T is available at Aetrix Electronics and suitable for telecom infrastructure, industrial automation, and automotive body electronics requiring stable component supply, extended temperature operation, and long-term lifecycle continuity.

Supply support for MAX6731AUTRD3+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, mixed-signal, and power management ICs for demanding industrial, automotive, and communications applications.

The MAX6730A–MAX6735A family delivers highly integrated, temperature-hardened µP supervisors with configurable voltage monitoring, dual-mode watchdogs, and flexible reset outputs - targeting systems where reliability under voltage stress and thermal extremes is non-negotiable.

FAQ

What is the exact VCC1 reset threshold voltage for MAX6731AUTRD3+T?

The MAX6731AUTRD3+T has a factory-set VCC1 reset threshold of +3.075V (R suffix), with ±2.5% tolerance across -40°C to +125°C and 0.5% hysteresis. This value is laser-trimmed during production and documented in Maxim's Ordering Information table for the RD3 variant.

Does MAX6731AUTRD3+T support manual reset, and how is it implemented?

Yes, MAX6731AUTRD3+T includes an active-low manual reset input (MR) on Pin 4. It features an internal 50kΩ pullup to VCC1, accepts CMOS-level signals, and requires a minimum 1µs low pulse to assert RST. The reset remains active for the full D3 timeout (140–280ms) after MR returns high.

What are the watchdog timeout periods for MAX6731AUTRD3+T?

MAX6731AUTRD3+T uses a dual-mode watchdog: an initial timeout of 35s–72s after any reset event (power-up, brownout, or MR), followed by a normal-mode timeout of 1.12s–2.24s. The watchdog clears on any WDI edge and asserts WDO low if no transition occurs within the active timeout window.

Is MAX6731AUTRD3+T compatible with bidirectional µP reset pins?

Yes, MAX6731AUTRD3+T's push-pull RST output can interface with bidirectional µP reset I/O by adding a 10kΩ series resistor between RST and the µP pin. This prevents logic contention during reset release and is explicitly recommended in Maxim's Applications Information section.

What package type and dimensions does MAX6731AUTRD3+T use?

MAX6731AUTRD3+T is supplied in a 6-pin SOT23-6 package (U6-1), measuring 2.9mm × 1.6mm × 1.1mm with gull-wing leads. It is RoHS-compliant and lead-free, indicated by the "+T" suffix per Maxim's ordering conventions.