Analog Devices Inc./Maxim Integrated MAX6361LUT31+T

Overview

MAX6361LUT31+T from Maxim Integrated is a low-power microprocessor supervisory circuit with factory-preset 3.08V reset threshold, manual reset input (MR), and active-low push-pull RESET output. It operates from +1.2V supply, provides battery switchover control for SRAM backup, guarantees RESET assertion down to 1.2V, and delivers 150ms minimum reset timeout - used in portable medical monitors requiring reliable brownout recovery and nonvolatile memory retention.

For engineers reviewing the MAX6361LUT31+T datasheet, MAX6361LUT31+T pinout, MAX6361LUT31+T application, or MAX6361LUT31+T equivalent, key selection criteria include its 3.08V precision reset threshold, MR debounced input with internal 20kΩ pull-up, SOT23-6 package footprint, battery switchover hysteresis of 40mV, and guaranteed operation across –40°C to +85°C industrial temperature range.

Technical Context

The MAX6361LUT31+T integrates a precision voltage monitor, debounced manual reset input with 1µs minimum pulse width immunity, and a push-pull reset driver capable of sinking 1.6mA at VCC ≥2.1V. Its internal comparator references a trimmed bandgap, delivering ±1.5% reset threshold accuracy over temperature.

Battery switchover logic activates when VCC falls below both the 3.08V threshold and VBATT by at least 20mV, connecting BATT to OUT via an internal MOSFET with on-resistance ≤2.7Ω at VBATT = 2.8V. Reset remains asserted for ≥150ms after VCC rises above 3.08V, independent of MR release timing.

Key Specifications

Pinout & Package

Package: 6-pin SOT23 (U6-1), 1.6mm × 2.9mm footprint, RoHS-compliant lead-free (+T suffix).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6361LUT31+T, the MAX6361LUT29+T offers lower threshold for 3.0V rails but identical functionality, while TPS3808G30DBVR reduces integration by omitting MR and battery control - making it unsuitable for SRAM backup designs requiring autonomous switchover.

Availability

MAX6361LUT31+T is available at Aetrix Electronics and suitable for portable medical devices, industrial PLCs, handheld scanners, and smart energy meters requiring stable component supply across extended product lifecycles.

Supply support for MAX6361LUT31+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) designs precision analog and mixed-signal ICs for industrial, automotive, and computing applications, with emphasis on reliability and low-power operation.

The MAX6361–MAX6364 family targets battery-backed microprocessor systems needing integrated reset, manual reset, and seamless power switchover - specifically engineered for SRAM retention in portable and critical infrastructure equipment.

FAQ

What is the exact reset threshold voltage of MAX6361LUT31+T and how tightly is it specified?

The MAX6361LUT31+T has a factory-trimmed reset threshold of 3.08V, with guaranteed tolerance of ±1.5% over the full –40°C to +85°C operating temperature range. This specification is confirmed in the Electrical Characteristics table of the official datasheet (Rev 4, October 2011), where VTH min = 3.00V and max = 3.15V at TA = –40°C to +85°C. The 3.08V value is the typical threshold at +25°C, and all units are 100% production tested at room temperature.

Does MAX6361LUT31+T support battery backup for SRAM, and how does the switchover logic work?

Yes, MAX6361LUT31+T supports autonomous battery backup for SRAM via its OUT pin. Switchover occurs when two conditions are met: VCC falls below the 3.08V reset threshold AND VCC drops at least 20mV below VBATT. An internal MOSFET then connects BATT to OUT, with on-resistance ≤2.7Ω at VBATT = 2.8V. When VCC recovers to VBATT + 20mV, the device switches back to VCC. This 40mV hysteresis prevents oscillation during slow brownouts - a behavior explicitly defined in the Pin Description and Detailed Description sections of the MAX6361–MAX6364 datasheet.

What type of RESET output does MAX6361LUT31+T provide, and what drive capability does it have?

MAX6361LUT31+T provides an active-low push-pull RESET output (pin 1), not open-drain. As specified in the Electrical Characteristics table, it can sink 1.6mA while maintaining VOL ≤ 0.4V at VCC ≥ 2.1V, and 3.2mA at VCC = 5V. This eliminates the need for an external pull-up resistor when driving standard µP reset inputs, simplifying layout and improving noise immunity compared to open-drain alternatives.

Can the manual reset input (MR) of MAX6361LUT31+T be left unconnected, and what happens if it is?

Yes, the MR pin of MAX6361LUT31+T can be left unconnected because it features an internal 20kΩ pull-up resistor to VCC. With MR floating or tied to VCC, the device operates normally - reset is asserted only when VCC falls below 3.08V or during power-up. If MR is pulled low externally, reset asserts immediately and remains active for ≥150ms after MR returns high. This behavior is documented in the Pin Description and Detailed Description sections, confirming no external components are needed for basic operation.

What is the minimum supply voltage at which MAX6361LUT31+T guarantees proper RESET assertion and release?

MAX6361LUT31+T guarantees correct RESET assertion and release down to +1.2V on either VCC or VBATT, as stated in the "Features" list and confirmed in the Absolute Maximum Ratings and Electrical Characteristics tables. Specifically, RESET remains valid (i.e., VOL ≤ 0.4V when asserted, VOH ≥ 0.8×VCC when released) even when VCC = 1.2V. This enables reliable operation in ultra-low-voltage battery systems where supply may sag to 1.2V before cutoff - a key differentiator versus competitors specifying minimum 1.6V or higher.