Analog Devices Inc./Maxim Integrated MAX6361HUT31+

Overview

MAX6361HUT31+ from Maxim Integrated is a low-power microprocessor supervisory circuit with manual reset input, factory-preset 3.08V reset threshold, active-low open-drain reset output, and battery switchover capability for SRAM backup. It operates from +1.2V supply, guarantees RESET/RESET validity down to 1.2V, and provides 150ms minimum reset timeout. Used in portable/battery-powered equipment requiring reliable brownout detection and power-fail warning.

For engineers reviewing the MAX6361HUT31+ datasheet, MAX6361HUT31+ pinout, MAX6361HUT31+ application, or MAX6361HUT31+ equivalent, key selection criteria include reset threshold accuracy (±1.5% over temperature), manual reset debounce integration, battery switchover hysteresis (40mV), supply current (15µA typical at 2.8V), and SOT23-6 package compatibility with space-constrained µP systems.

Technical Context

The MAX6361HUT31+ implements a precision voltage monitor with internal 1.235V reference and resistor-divider scaling to achieve its 3.08V reset threshold. Its manual reset input (MR) features an integrated 20kΩ pull-up and 120ns propagation delay, enabling direct switch connection without external debounce components.

Battery switchover uses dual-MOSFET architecture: VCC powers OUT above threshold; when VCC falls below VBATT − 0.2V, BATT automatically connects to OUT with on-resistance as low as 2.63Ω at 2.8V. Reset assertion remains valid during brownout due to guaranteed 1.2V operation of both VCC and VBATT rails.

Key Specifications

Pinout & Package

Package: 6-pin SOT23 (U6-1 outline, 2.9mm × 1.6mm footprint, 1.1mm height). RoHS-compliant lead-free construction with + suffix.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6361HUT29+ and TPS3808G33DBVR, the MAX6361HUT31+ uniquely combines 3.08V precision threshold, integrated MR pull-up, and battery switchover in one SOT23-6 device-making it irreplaceable where SRAM backup and field-service reset coexist in space-constrained designs.

Availability

MAX6361HUT31+ is available at Aetrix Electronics and suitable for portable medical devices, industrial PLC modules, smart energy meters, and POS terminals requiring stable component supply across automotive-grade temperature ranges and long-lifecycle production programs.

Supply support for MAX6361HUT31+ 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 power, sensing, and connectivity applications in industrial, computing, and consumer markets.

The MAX6361–MAX6364 family targets battery-backed µP systems requiring integrated reset, manual reset, and power switchover-replacing discrete solutions with a single low-quiescent-current SOT23 device.

FAQ

What is the exact reset threshold voltage of the MAX6361HUT31+?

The MAX6361HUT31+ has a factory-trimmed reset threshold of 3.08V, with ±1.5% accuracy over the full −40°C to +85°C operating temperature range. This value is confirmed in the Ordering Information table and Electrical Characteristics section of the MAX6361–MAX6364 datasheet, and applies specifically to the "31" suffix variant. The MAX6361HUT31+ uses this threshold to monitor +3.3V supplies with appropriate margin against tolerance drift.

Does the MAX6361HUT31+ support battery backup functionality?

Yes, the MAX6361HUT31+ supports automatic battery switchover: when VCC falls below VBATT − 0.2V, it disconnects VCC from OUT and connects BATT to OUT with ≤2.7Ω on-resistance. The device remains in battery-backup mode until VCC rises 20mV above VBATT. This behavior is documented in the Pin Description and Detailed Description sections, and is intrinsic to all MAX6361–MAX6364 variants including the MAX6361HUT31+.

What type of reset output does the MAX6361HUT31+ provide?

The MAX6361HUT31+ provides an active-low open-drain RESET output (pin 1), as specified in the Selector Guide and Pin Configurations diagram. It requires an external pull-up resistor to generate a logic-high level during normal operation. This configuration allows wired-OR connection with other reset sources and is compatible with standard µP reset inputs. The "H" in the part number denotes the open-drain active-low version.

Can the MAX6361HUT31+ operate with a 1.2V supply?

Yes, the MAX6361HUT31+ guarantees full functionality-including RESET/RESET assertion and validity-down to 1.2V on either VCC or VBATT. This is explicitly stated in the Features list and confirmed in the Absolute Maximum Ratings and Electrical Characteristics tables. Operation at 1.2V enables compatibility with single-cell Li+ batteries and ultra-low-power systems where supply rails decay deeply before shutdown.

Is there an internal pull-up resistor on the MR pin of the MAX6361HUT31+?

Yes, the MAX6361HUT31+ includes a 20kΩ internal pull-up resistor on the MR pin (pin 3), as documented in the Pin Description and Detailed Description sections. This eliminates the need for an external pull-up and allows direct connection of a momentary switch between MR and GND. The MR input is debounced internally, so no external RC network is required-this feature is specific to the MAX6361HUT31+ and other MAX6361 variants.