Analog Devices Inc./Maxim Integrated MAX6326UR25+T

Overview

MAX6326UR25+T from Maxim Integrated is an ultra-low-power, active-low push-pull microprocessor supervisory circuit designed to monitor 2.5V power supplies and assert a reset signal during brownout or power-up conditions. It features a factory-trimmed 2.500V reset threshold (±1.5% at +25°C, ±2.5% over –40°C to +85°C), 100ms minimum reset timeout, 1µA maximum supply current at 3V, and operates down to 1.2V VCC. It is used in portable battery-powered systems requiring reliable, low-quiescent-power reset supervision.

For engineers reviewing the MAX6326UR25+T datasheet, MAX6326UR25+T pinout, MAX6326UR25+T application, or MAX6326UR25+T equivalent, key selection criteria include its SOT23-3 package, push-pull active-low RESET output, guaranteed operation down to 1.2V, immunity to fast VCC transients, and compatibility with 2.5V µP power rails.

Technical Context

The MAX6326UR25+T implements a precision bandgap-based voltage comparator with hysteresis (6.3mV) to detect VCC falling below 2.500V, triggering an active-low RESET assertion. Its internal timing circuit guarantees a minimum 100ms reset pulse width after VCC recovers above threshold, independent of supply ramp rate.

Designed for direct integration into space-constrained embedded systems, it requires no external components, supports bidirectional µP reset interfaces via its push-pull driver, and rejects negative-going VCC transients up to 200µs at 200mV overdrive - confirmed by Maxim's Typical Operating Characteristics graphs.

Key Specifications

Pinout & Package

MAX6326UR25+T is housed in a 3-pin SOT23-3 package (package code U3-1), with 0.95mm pitch, 2.9mm × 1.6mm footprint, and exposed pad not present. Pin 1 = GND, Pin 2 = RESET (active-low push-pull), Pin 3 = VCC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326UR25+T, MAX809TRD3+T trades 1.5µA higher quiescent current for broader legacy availability, while TPS3125N25DBVR offers lower ICC but mandates external biasing - making MAX6326UR25+T optimal for noise-immune, component-minimized 2.5V reset designs.

Availability

MAX6326UR25+T is available at Aetrix Electronics and suitable for portable medical devices, industrial I/O modules, and smart energy metering systems requiring stable component supply, long-lifecycle support, and RoHS-compliant sourcing.

Supply support for MAX6326UR25+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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.

The MAX6326 family was engineered specifically for ultra-low-power, precision reset supervision in battery-operated and space-constrained embedded systems - prioritizing sub-µA ICC, factory-trimmed thresholds, and robust transient immunity without external components.

FAQ

What is the exact reset threshold voltage of MAX6326UR25+T and how does it vary with temperature?

The MAX6326UR25+T has a nominal reset threshold of 2.500V, trimmed at +25°C with ±1.5% tolerance. Over the full –40°C to +85°C operating range, the threshold varies by ±2.5%, resulting in a guaranteed range of 2.437V to 2.562V. Its 40ppm/°C tempco ensures predictable, linear drift - adding less than 12mV total shift across the temperature span. This stability is critical for consistent 2.5V rail supervision in unregulated environments where MAX6326UR25+T is deployed.

Does MAX6326UR25+T require any external components to function as a reset supervisor?

No, MAX6326UR25+T requires zero external components. It integrates a precision voltage reference, comparator, hysteresis circuit, and push-pull output driver in a single SOT23-3 package. Unlike RC-based reset circuits, MAX6326UR25+T delivers guaranteed 100ms reset timeout, factory-calibrated threshold, and transient immunity without resistors, capacitors, or trimming. This simplifies design validation and improves long-term reliability - a key reason MAX6326UR25+T is specified in safety-critical and maintenance-free applications.

What is the minimum VCC voltage at which MAX6326UR25+T continues to assert a valid reset signal?

MAX6326UR25+T guarantees correct reset assertion down to VCC = 1.2V over the full –40°C to +85°C temperature range. Below 1.2V, the device may enter undefined state; however, its internal circuitry remains functional and will reassert RESET as soon as VCC rises above the 2.500V threshold - even if VCC subsequently drops again. This 1.2V operational floor makes MAX6326UR25+T uniquely suited for deep brownout detection in battery-powered systems where MAX6326UR25+T must supervise until near-exhaustion.

How does the push-pull output of MAX6326UR25+T differ from open-drain alternatives in system design?

The push-pull output of MAX6326UR25+T actively drives both high and low states on the RESET line, eliminating the need for an external pull-up resistor. This reduces component count, saves PCB area, and avoids timing uncertainty introduced by RC time constants. In contrast, open-drain supervisors like MAX6328 require a pull-up, increasing leakage paths and complicating noise immunity. For µPs with dedicated reset inputs (e.g., ARM Cortex-M series), MAX6326UR25+T's push-pull drive ensures faster, more deterministic reset release - a verified behavior in MAX6326UR25+T's electrical specs.

Is MAX6326UR25+T pin-compatible with other common reset ICs such as the MAX809 series?

Yes, MAX6326UR25+T is pin-compatible with the MAX803/MAX809/MAX810 family in the SOT23-3 package: Pin 1 = GND, Pin 2 = RESET, Pin 3 = VCC. However, functional differences exist - MAX6326UR25+T offers 1µA ICC (vs. 2.5µA for MAX809), tighter threshold tolerance (±1.5% vs. ±2.5%), and specified transient immunity. While drop-in replacement is mechanically possible, designers should verify timing and noise performance requirements before substituting MAX6326UR25+T into legacy MAX809 designs.