Analog Devices Inc./Maxim Integrated MAX6326XR31

Overview

MAX6326XR31 from Maxim Integrated is an ultra-low-power, active-low push-pull microprocessor supervisory circuit designed to monitor 3.08V power supplies and assert a reset signal during brownout, power-up, or power-down events. It guarantees correct reset state down to VCC = 1.2V, delivers ≥100ms reset timeout after VCC recovery, and draws ≤1µA supply current at +25°C - making it ideal for battery-powered embedded controllers requiring reliable, low-cost power monitoring.

For engineers reviewing the MAX6326XR31 datasheet, MAX6326XR31 pinout, MAX6326XR31 application, or MAX6326XR31 equivalent, key selection considerations include its factory-trimmed 3.08V reset threshold (±2.5% over –40°C to +85°C), SC70-3 package compatibility, open-drain vs. push-pull output distinction within the family, and immunity to sub-20µs VCC transients at 100mV overdrive.

Technical Context

The MAX6326XR31 implements a precision bandgap-based voltage comparator with built-in hysteresis (6.3mV) to detect VCC drops below its 3.08V threshold. Its internal timing circuit ensures a minimum 100ms reset assertion after VCC rises above threshold, independent of supply ramp rate.

It features push-pull RESET output logic with VOH ≥ 0.8·VCC (ISOURCE = 500µA, VCC ≥ 2.1V) and VOL ≤ 0.3V (ISINK = 1.6mA, VCC > 2.1V), enabling direct interface with standard CMOS inputs without external pull-ups. The device operates across the full industrial temperature range (–40°C to +85°C) with guaranteed functionality down to VCC = 1.2V.

Key Specifications

Pinout & Package

MAX6326XR31 is housed in a 3-pin SC70-3 package (outline X3-2, land pattern 90-0208), measuring 2.0mm × 2.1mm × 0.95mm, with gull-wing leads and RoHS-compliant lead-free finish (marked "ACE" on top).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326UR31-T, MAX6326XR31-T saves 0.9mm² board area and improves thermal response; compared with MAX809TR31-T, it reduces supply current by 60% and extends functional VCC range downward by 300mV - critical for energy-harvesting and long-life battery systems.

Availability

MAX6326XR31 is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical sensors, and smart energy meters requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX6326XR31 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 analog, mixed-signal, and power-management ICs for industrial, communications, and consumer applications.

The MAX6326 family was designed specifically for cost-sensitive, space-constrained microprocessor systems needing ultra-low-power, precision voltage supervision with minimal external components.

FAQ

What is the exact reset threshold voltage of MAX6326XR31 and how tightly is it specified?

The MAX6326XR31 has a factory-trimmed nominal reset threshold of 3.08V, with a tolerance of ±2.5% over the full industrial temperature range (–40°C to +85°C). At +25°C, this tightens to ±1.5%, meaning the actual threshold falls between 3.034V and 3.126V under room-temperature conditions. This precision eliminates the need for external trimming components and ensures consistent brownout detection across production units.

Does MAX6326XR31 support operation at VCC voltages below 2.0V, and why does that matter?

Yes, MAX6326XR31 is fully specified to operate and assert valid reset down to VCC = 1.2V - well below typical 2.0V cutoffs. This capability is essential in battery-powered systems where the supply may sag deeply during peak load or end-of-life, ensuring the microcontroller remains held in reset until the rail recovers sufficiently for reliable operation. Without this feature, premature release could cause erratic firmware execution or memory corruption.

How does the push-pull output of MAX6326XR31 differ from open-drain alternatives like MAX6328XR31?

The MAX6326XR31 uses a push-pull RESET output, actively driving both high and low states, whereas MAX6328XR31 uses open-drain logic requiring an external pull-up resistor. This means MAX6326XR31 simplifies design by eliminating the pull-up component, reduces PCB area, and ensures faster high-to-low and low-to-high transitions - critical for systems with strict reset timing budgets or where board space is constrained.

What is the maximum duration of VCC transients that MAX6326XR31 can ignore without asserting reset?

MAX6326XR31 ignores negative-going VCC transients up to 20µs in duration when the overdrive (VTH – VCC) is 100mV, as confirmed by the "Maximum Transient Duration vs. Reset Threshold Overdrive" graph in the datasheet. This immunity prevents false resets caused by switching noise or coupling spikes, especially important in motor-drive or RF-heavy environments where power rails experience fast, shallow dips.

Is MAX6326XR31 pin-compatible with older Maxim supervisors like MAX803 or MAX809?

Yes, MAX6326XR31 is pin-compatible with MAX803/MAX809/MAX810 in both SC70-3 and SOT23-3 packages - sharing identical 3-pin pinout (VCC, RESET, GND) and footprint dimensions. This allows drop-in replacement in existing designs to gain benefits of lower supply current (1µA vs. 2.5µA), tighter threshold tolerance, and extended VCC operating range without PCB layout changes.