Analog Devices Inc./Maxim Integrated MAX6327UR28

Overview

MAX6327UR28 from Maxim Integrated is an active-high push-pull microprocessor supervisory circuit designed to monitor VCC supply voltage and assert a reset signal during power-up, brownout, or power-down events. It features a factory-trimmed 2.80V reset threshold (±1.5% at +25°C, ±2.5% over -40°C to +85°C), 100ms minimum reset timeout, ultra-low 1µA max supply current, and guaranteed operation down to 1.2V VCC. It is used in portable battery-powered systems requiring reliable, low-power reset supervision.

For engineers reviewing the MAX6327UR28 datasheet, MAX6327UR28 pinout, MAX6327UR28 application, or MAX6327UR28 equivalent, this page provides verified functional identity, confirmed SOT23-3 package mapping, validated active-high push-pull output behavior, exact reset threshold tolerance across temperature, and real-world design implications of its 100ms timeout and transient immunity.

Technical Context

The MAX6327UR28 implements a precision bandgap-based reset comparator with built-in hysteresis (6.3mV) and internal timing capacitor for fixed 100ms–280ms reset assertion after VCC recovery. Its active-high push-pull RESET output drives high (≥0.8·VCC) when asserted and low (≤0.4V at 3.2mA sink) when deasserted, eliminating external pull-up components.

It operates across full industrial temperature range (-40°C to +85°C) with VCC supply range of 1.2V to 5.5V, supports fast VCC transients up to 100V/µs, and maintains reset state integrity down to 1V VCC - ensuring deterministic behavior during deep brownout conditions before full power collapse.

Key Specifications

Pinout & Package

MAX6327UR28 is housed in a 3-pin SOT23-3 package (outline U3-1), footprint-compatible with industry-standard SC70-3 but with higher power dissipation rating (320mW at +70°C).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6327UR28, MAX6327XR28-T offers identical functionality in a smaller package but reduced thermal headroom, while TPS3123QDBVRQ1 adds automotive qualification at the cost of higher current draw, different output topology, and non-pin-compatible layout.

Availability

MAX6327UR28 is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC I/O modules, smart utility meters, and automotive body control modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MAX6327UR28 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 industrial, communications, and consumer applications, with emphasis on power efficiency and integration.

The MAX6326/MAX6327/MAX6328 family was engineered specifically for ultra-low-power microprocessor reset supervision in battery-critical and thermally constrained systems, prioritizing sub-µA current and guaranteed low-VCC operation.

FAQ

What is the exact reset threshold voltage of MAX6327UR28 and how does it vary with temperature?

The MAX6327UR28 has a factory-trimmed nominal reset threshold of 2.80V. At +25°C, this is guaranteed between 2.756V and 2.844V (±1.5%). Over the full industrial temperature range (-40°C to +85°C), the threshold stays within 2.730V to 2.870V (±2.5%). This tight tolerance ensures consistent reset behavior across environments without recalibration. The MAX6327UR28 uses internal bandgap referencing and laser trimming to achieve this stability.

Does MAX6327UR28 require any external components to function?

No, the MAX6327UR28 requires zero external components. Its internal precision voltage reference, comparator, and timing capacitor eliminate the need for external resistors, capacitors, or pull-up resistors. The active-high push-pull RESET output connects directly to the microprocessor's reset input. This simplifies design, reduces BOM cost, and improves reliability - a key advantage confirmed in the MAX6327UR28 datasheet and application circuits.

Can MAX6327UR28 operate reliably during severe power supply transients?

Yes, the MAX6327UR28 is specifically designed to ignore fast negative-going VCC transients. It tolerates glitches up to 200µs wide when the overdrive (VTH − VCC) is 200mV, and shorter durations at larger overdrives - per the "Maximum Transient Duration vs. Reset Threshold Overdrive" graph in the MAX6327UR28 datasheet. Its comparator also rejects dV/dt up to 100V/µs, making it robust against switching noise and ESD-induced supply disturbances.

What is the minimum VCC voltage at which MAX6327UR28 guarantees correct reset state?

The MAX6327UR28 guarantees correct reset assertion and deassertion down to VCC = 1.2V over the full temperature range (-40°C to +85°C), and remains functional (though not fully specified) down to 1.0V. This ensures deterministic behavior during deep brownout - for example, when a lithium battery discharges below 2.5V. The MAX6327UR28 maintains valid logic levels on its RESET pin even at these low voltages, unlike many competing supervisors.

Is MAX6327UR28 pin-compatible with older Maxim reset ICs like MAX809?

Yes, the MAX6327UR28 is pin-compatible with MAX809, MAX803, and MAX810 in the same SOT23-3 package. Pin 1 is GND, Pin 2 is RESET (active-high push-pull), and Pin 3 is VCC - matching the physical layout and electrical interface. However, the MAX6327UR28 offers superior specs: 1µA vs. 20µA supply current, tighter threshold tolerance, and guaranteed operation down to 1.2V VCC. Migration to MAX6327UR28 requires no PCB changes.