Analog Devices Inc./Maxim Integrated MAX6344LUT+T

Overview

MAX6344LUT+T from Maxim Integrated is a precision microprocessor supervisory circuit with active-high push-pull reset output, factory-trimmed 4.63V VCC reset threshold, +1.25V power-fail comparator input, and guaranteed RESET validity down to VCC = +1V. It operates across -40°C to +125°C in 6-pin SOT23 and is used in telecom equipment for reliable power-up sequencing and brownout protection.

For engineers reviewing the MAX6344LUT+T datasheet, MAX6344LUT+T pinout, MAX6344LUT+T application, or MAX6344LUT+T equivalent, this device delivers deterministic reset timing, low-quiescent-current supervision (25µA typical), dual-voltage monitoring capability, and robust immunity to VCC transients - critical for multivoltage embedded systems requiring fail-safe boot integrity.

Technical Context

The MAX6344LUT+T integrates a precision bandgap reference, reset timeout generator, and independent power-fail comparator. Its reset assertion is triggered when VCC falls below 4.63V (±25mV over temperature), with minimum 100ms reset pulse width and guaranteed logic-level output down to VCC = +1V.

It features a dedicated PFI input referenced to +1.25V for early power-fail warning or secondary supply monitoring, and a CMOS-compatible MR input with 1µs glitch rejection. The active-high push-pull RESET output drives up to 800µA at VCC ≥ 4.5V without external pull-up.

Key Specifications

Pinout & Package

Package: 6-pin SOT23-6, surface-mount, lead-free (RoHS-compliant), thermal pad not present.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6342LUT+T and TLV809KDBZR, the MAX6344LUT+T uniquely combines active-high reset drive, integrated power-fail warning, and manual reset in a 6-pin SOT23 - enabling compact, feature-complete supervision without external components or logic inversion.

Availability

MAX6344LUT+T is available at Aetrix Electronics and suitable for telecom equipment, industrial PLC controllers, and battery-powered test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6344LUT+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, mixed-signal, and power management ICs for industrial, automotive, communications, and computing applications.

The MAX6342–MAX6345 family was engineered specifically for high-reliability microprocessor supervision in multivoltage systems - delivering factory-trimmed accuracy, wide temperature operation, and integrated power-fail detection in miniature packages.

FAQ

What is the exact reset threshold voltage of the MAX6344LUT+T?

The MAX6344LUT+T has a factory-trimmed VCC reset threshold of 4.63V, with a maximum tolerance of ±25mV over the full -40°C to +125°C operating temperature range. This value is laser-trimmed during production and specified in the Electrical Characteristics table of the official datasheet. The 'L' suffix in MAX6344LUT+T explicitly denotes the 4.63V variant, and the threshold remains stable under load and across supply voltage variations from +1.0V to +5.5V.

Does the MAX6344LUT+T require an external pull-up resistor on its RESET pin?

No, the MAX6344LUT+T does not require an external pull-up resistor on its RESET pin because it features an active-high push-pull output stage. Unlike open-drain variants (e.g., MAX6343), the MAX6344LUT+T actively drives the RESET line high after VCC rises above 4.63V or MR is released, and holds it high for ≥100ms. This eliminates external components and ensures fast, low-impedance assertion compatible with modern µPs and FPGAs requiring active-high reset inputs.

How is the power-fail warning function implemented in the MAX6344LUT+T?

The MAX6344LUT+T implements power-fail warning via its dedicated PFI (Power-Fail Input) and PFO (Power-Fail Output) pins. The internal +1.25V comparator monitors voltage applied to PFI; when that voltage falls below +1.25V, PFO goes low. To monitor a secondary supply (e.g., +3.3V), a resistor divider scales the rail to 1.25V at the trip point. PFO can then be routed to a µP interrupt pin to initiate controlled shutdown before main supply collapse - a capability not present in basic reset-only supervisors like the TLV809 series.

Can the MAX6344LUT+T operate reliably during deep brownout conditions?

Yes, the MAX6344LUT+T is guaranteed to assert and maintain a valid logic-high RESET signal down to VCC = +1.0V, per the Absolute Maximum Ratings and Electrical Characteristics tables. This ensures deterministic behavior during severe brownouts where other supervisors may release reset prematurely. The internal reference and comparator remain functional across the full +1.0V to +5.5V supply range, and the 100ms minimum timeout persists regardless of VCC level - making MAX6344LUT+T suitable for mission-critical systems exposed to unstable power sources.

What is the purpose of the MR (Manual Reset) input on the MAX6344LUT+T?

The MR input on the MAX6344LUT+T provides a CMOS-compatible, debounced active-low signal path to force a system reset independently of VCC monitoring. Pulling MR low for ≥1µs triggers a full reset cycle: RESET goes high after MR returns high and remains asserted for ≥100ms. This enables front-panel reset buttons, remote watchdog resets, or debug-initiated restarts without requiring power rail cycling. MR is internally debounced, so no external RC filter is needed - simplifying board layout and improving reliability in noisy industrial environments.