Analog Devices Inc./Maxim Integrated MAX6327UR31-T

Overview

MAX6327UR31-T from Maxim Integrated is an active-high push-pull microprocessor supervisory circuit that monitors VCC supply voltage and asserts a reset signal when voltage drops below 3.08V, maintaining reset for ≥100ms after recovery; it operates from 1.2V to 5.5V, draws ≤1µA supply current, and is housed in a 3-pin SOT23-3 package for portable and embedded power-monitoring applications.

For engineers reviewing the MAX6327UR31-T datasheet, MAX6327UR31-T pinout, MAX6327UR31-T application, or MAX6327UR31-T equivalent, this device serves as a precision, ultra-low-power reset supervisor for 3.3V systems requiring guaranteed reset assertion down to 1V VCC, transient-immune brownout detection, and factory-trimmed threshold accuracy of ±2.5% over –40°C to +85°C.

Technical Context

The MAX6327UR31-T implements a precision bandgap-based reset comparator with 3.08V nominal threshold (±2.5% over temperature), hysteresis of 6.3mV, and immunity to fast VCC transients up to 100V/µs. Its active-high push-pull output drives high during reset (≥0.8·VCC at 500µA) and low otherwise (≤0.4V at 3.2mA), eliminating external pull-up components.

Designed for single-function supervision, it requires no external timing or biasing components, delivers a minimum 100ms reset timeout after power-up, and guarantees correct logic state across its full 1.2V–5.5V VCC range - enabling reliable operation in battery-backed and low-voltage microcontroller systems.

Key Specifications

Pinout & Package

MAX6327UR31-T is supplied in a 3-pin SOT23-3 package (package code U3-1), with 1.3mm × 2.9mm footprint and 0.95mm height, compatible with standard pick-and-place assembly and reflow soldering.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809TR31D3-T and TPS3808G33DBVR, the MAX6327UR31-T offers the lowest supply current (≤1µA), push-pull output eliminating external components, and guaranteed functionality down to 1.2V V_CC - making it optimal for ultra-low-power, space-constrained 3.3V embedded systems where reset reliability under brownout is critical.

Availability

MAX6327UR31-T is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical monitors, smart energy meters, and automotive body control modules requiring stable component supply, long-lifecycle support, and RoHS-compliant sourcing.

Supply support for MAX6327UR31-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 is a semiconductor company specializing in analog and mixed-signal ICs for power, interface, sensing, and timing applications, now part of Analog Devices.

The MAX6326/MAX6327/MAX6328 family was designed specifically for ultra-low-power microprocessor reset supervision in battery-powered and space-constrained embedded systems, emphasizing precision threshold accuracy, minimal quiescent current, and robust transient immunity.

FAQ

What is the exact reset threshold voltage of MAX6327UR31-T and how tightly is it specified?

The MAX6327UR31-T has a nominal reset threshold of 3.08V, factory-trimmed with ±1.5% tolerance at +25°C and ±2.5% over the full –40°C to +85°C operating temperature range. This specification is guaranteed in production testing and documented in the Electrical Characteristics table of the official datasheet. The "R31" suffix explicitly denotes the 3.08V variant within the MAX6327 family.

Does MAX6327UR31-T require any external components to function as a reset supervisor?

No, the MAX6327UR31-T requires no external components. Its active-high push-pull output eliminates the need for an external pull-up resistor, and its internal precision voltage reference and timing circuitry remove requirements for capacitors or resistors. This enables direct connection between V_CC, GND, and the target microcontroller's reset pin - reducing BOM count and PCB area.

What is the minimum V_CC voltage at which MAX6327UR31-T guarantees correct reset assertion and release behavior?

The MAX6327UR31-T guarantees correct reset assertion and release behavior down to V_CC = 1.2V over the full –40°C to +85°C temperature range. At room temperature, it remains functional down to 1.0V. This ensures deterministic reset operation during deep brownout or battery depletion scenarios where other supervisors may fail to assert or release reliably.

How does the MAX6327UR31-T handle fast transients on the V_CC supply line?

The MAX6327UR31-T incorporates a comparator architecture designed to reject fast V_CC transients, with a specified maximum input slew rate immunity of 100V/µs. Its internal hysteresis (6.3mV) and filtering prevent false resets during short-duration negative-going glitches - a key requirement in electrically noisy environments such as industrial motor controls or automotive subsystems.

Is MAX6327UR31-T pin-compatible with legacy Maxim reset supervisors like the MAX809 series?

Yes, the MAX6327UR31-T is pin-compatible with the MAX809 series in the same SOT23-3 package, sharing identical pinout (V_CC, RESET, GND). However, unlike the open-drain MAX809, the MAX6327UR31-T features an active-high push-pull output - meaning it can directly drive a µP reset pin without an external pull-up, simplifying design while maintaining mechanical and layout compatibility.