Analog Devices Inc./Maxim Integrated MAX6351LRUT

Overview

MAX6351LRUT from Maxim Integrated is a dual-voltage microprocessor supervisory circuit with two independent active-low push-pull reset outputs-one referenced to VCC1 (4.63V threshold) and one to VCC2 (2.63V threshold)-designed for multivoltage systems requiring simultaneous monitoring of +5V and +3.3V rails. It guarantees valid RESET output down to VCC1 ≥ 1.0V or VCC2 ≥ 1.0V, features 20µA supply current, and operates across –40°C to +85°C.

For engineers reviewing the MAX6351LRUT datasheet, MAX6351LRUT pinout, MAX6351LRUT application, or MAX6351LRUT equivalent, key selection considerations include dual-supply reset assertion logic, push-pull output drive capability per rail, voltage threshold accuracy (±1.5% over temperature), and compatibility with manual-reset and transient-immune power sequencing in embedded controllers and portable equipment.

Technical Context

The MAX6351LRUT implements independent precision voltage comparators for VCC1 and VCC2, each with factory-trimmed thresholds (4.63V ±1.5% and 2.63V ±1.5%), hysteresis of VTH/500, and tempco of 20ppm/°C. Reset assertion occurs if either supply falls below its trip point, and outputs remain valid as long as at least one supply exceeds +1.0V.

It uses internal glitch filtering on MR input (100ns rejection), provides 100ms minimum power-on-reset pulse width, and supports debounced TTL/CMOS-compatible manual reset. No watchdog timer or third-voltage monitor is present-this variant is strictly dual-supply, non-watchdog, non-RSTIN.

Key Specifications

Pinout & Package

MAX6351LRUT is housed in a 6-pin SOT23 package (U6-1 outline, land pattern 90-0175), with exposed pad not electrically connected. The package supports leaded and RoHS-compliant (Pb-free) variants; ordering suffix "+T" denotes lead-free.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6351LRUT, MAX6353LRUK-T sacrifices VCC2 supervision and second reset output to reduce footprint and cost, while TPS3808G33DBVR lacks dual-rail capability entirely and introduces external component dependencies-neither offers pin-compatible replacement or identical functionality.

Availability

MAX6351LRUT is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical monitors, automotive body control modules, and network router power sequencing requiring stable component supply, guaranteed long-term availability, and RoHS-compliant packaging.

Supply support for MAX6351LRUT 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 high-performance analog and mixed-signal ICs for industrial, communications, and computing applications, with emphasis on reliability, precision, and low-power operation.

The MAX6351–MAX6360 family delivers multivoltage µP supervision with factory-trimmed thresholds, minimal external components, and robust operation across extended temperature ranges-targeting systems where power integrity and deterministic reset behavior are critical.

FAQ

What is the exact reset threshold voltage for VCC1 and VCC2 on the MAX6351LRUT?

The MAX6351LRUT has a VCC1 reset threshold of 4.63V (±1.5% over –40°C to +85°C) and a VCC2 threshold of 2.63V (±1.5% over temperature). These values are factory-trimmed and specified in the Voltage-Threshold Levels table; the "LR" suffix explicitly denotes this combination. Both thresholds are guaranteed across the full operating temperature range.

Does the MAX6351LRUT include a watchdog timer or third-voltage monitor?

No, the MAX6351LRUT does not include a watchdog timer or RSTIN input. It is a dual-supply-only variant-confirmed by its part number position in the selector guide and absence of WDI or RSTIN pins in its pin configuration. Watchdog functionality is exclusive to MAX6358–MAX6360, and third-voltage monitoring is limited to MAX6355–MAX6357.

Can the MAX6351LRUT operate with supply voltages below 1.2V?

The MAX6351LRUT guarantees valid RESET output as long as either VCC1 ≥ 1.0V or VCC2 ≥ 1.0V, but its specified operating range begins at VCC1/VCC2 = +1.2V (min) per Electrical Characteristics. Operation below 1.2V is outside guaranteed specs-designs requiring sub-1.2V operation should verify functionality empirically and consult Maxim's application notes for brownout edge cases.

What is the maximum load the MAX6351LRUT RST1 and RST2 outputs can drive?

The MAX6351LRUT RST1 and RST2 outputs are active-low push-pull drivers capable of sinking 1.2mA at VCC ≥ 2.7V (VOL ≤ 0.3V) and 3.2mA at VCC ≥ 4.5V (VOL ≤ 0.4V). This allows direct interface to standard CMOS/TTL reset inputs without external pull-ups-verified across –40°C to +85°C and documented in the Electrical Characteristics table.

Is the MAX6351LRUT pin-compatible with other devices in the MAX6351–MAX6360 family?

The MAX6351LRUT shares the same 6-pin SOT23 (U6-1) package and pinout with MAX6355–MAX6360, but not with 5-pin variants (e.g., MAX6352–MAX6354). However, pin function differs across subfamilies: MAX6355 uses Pin 5 as RSTIN, MAX6358 uses it as WDI, while MAX6351LRUT uses Pin 5 exclusively as RST2-so PCB layout is not interchangeable without verification of signal routing and function mapping.