Analog Devices Inc./Maxim Integrated MAX6449UT46L+T

Overview

MAX6449UT46L+T from Maxim Integrated is a dual-supply microprocessor reset supervisor IC featuring one fixed-threshold (4.625V) and one adjustable-threshold (0.63V reference) voltage monitor, two extended-setup manual reset inputs (MR1/MR2), push-pull active-low RESET output, and 6.72s minimum manual reset setup period. It ensures reliable system initialization in consumer electronics and industrial equipment where nuisance resets from short switch closures must be avoided.

For engineers reviewing the MAX6449UT46L+T datasheet, MAX6449UT46L+T pinout, MAX6449UT46L+T application, or MAX6449UT46L+T equivalent, key selection considerations include its dual-monitor architecture with factory-set VCC threshold and external resistor-divider–based RSTIN monitoring, guaranteed reset assertion down to VCC = 1.0V, 210ms typical timeout, and SOT23-6 package compatibility with high-reliability embedded power sequencing.

Technical Context

The MAX6449UT46L+T implements two independent reset comparators: one monitors VCC against a precision 4.625V threshold (±130mV max deviation), while the other monitors an externally derived voltage at RSTIN using a 0.630V ±20mV internal reference. Both comparators feed into a shared reset timing engine that asserts RESET low for 140ms minimum after any monitored supply falls below threshold or after MR1/MR2 are held low simultaneously for ≥6.72s.

Its dual manual reset architecture requires simultaneous low assertion of MR1 and MR2 for the full setup period to trigger a one-shot reset pulse-preventing false triggers from single-button presses-while maintaining internal 50kΩ pullups on both inputs and supporting glitch rejection up to 100ns on MR2. The push-pull RESET output guarantees valid logic state down to VCC = 1.0V with VOL ≤ 0.3V at 1.2V supply and 100µA sink current.

Key Specifications

Pinout & Package

MAX6449UT46L+T is housed in a 6-pin SOT23 package (outline 21-0058) with gull-wing leads, 0.95mm pitch, and RoHS-compliant lead-free plating (+T suffix). The package measures 2.9mm × 1.6mm × 1.1mm and supports reflow soldering per JEDEC J-STD-020 (260°C peak).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6449UT46L+T, MAX6450UT46L+T trades push-pull drive for open-drain flexibility at the cost of added BOM component, while MAX6449UT44L+T shifts the fixed threshold downward-requiring careful voltage-margin analysis before substitution in existing 4.625V-critical designs.

Availability

MAX6449UT46L+T is available at Aetrix Electronics and suitable for set-top boxes, cable modems, industrial HMIs, and medical monitoring devices requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MAX6449UT46L+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 power management, sensing, and interface applications, with emphasis on reliability and integration for demanding industrial and consumer systems.

The MAX6443–MAX6452 family was developed specifically for robust microprocessor supervision in noise-prone, front-panel–interfaced electronics-delivering extended manual reset immunity, dual-rail monitoring, and guaranteed operation down to 1.0V VCC.

FAQ

What is the exact VCC reset threshold voltage for MAX6449UT46L+T?

The MAX6449UT46L+T has a factory-set VCC reset threshold of 4.625V, with a maximum deviation of ±130mV over the full -40°C to +85°C operating temperature range. This value is confirmed in the Electrical Characteristics table under "VCC Reset Threshold" with suffix "46", and applies specifically to the MAX6449UT46L+T-not to other variants in the MAX6449 series. The threshold is trimmed during production and does not require external calibration.

How does the RSTIN pin function in MAX6449UT46L+T?

The RSTIN pin in MAX6449UT46L+T connects to an internal 0.630V ±20mV precision reference comparator, enabling monitoring of voltages below the VCC rail via an external resistor divider. Using the formula VMON-TH = 0.63V × (R1 + R2)/R2, designers can set custom reset thresholds-for example, 3.3V with R2 = 250kΩ and R1 ≈ 1.15MΩ. RSTIN draws only ±25nA, minimizing divider current consumption.

What is the purpose of the dual manual reset inputs (MR1 and MR2) on MAX6449UT46L+T?

MR1 and MR2 on MAX6449UT46L+T implement a dual-activation safety mechanism: both inputs must be held low simultaneously for the full 6.72s (L-suffix) setup period to assert RESET. This prevents accidental resets from single-button presses-common in consumer front panels-and enforces deliberate operator action. Each input includes a 50kΩ internal pullup to VCC, eliminating external bias components.

Does MAX6449UT46L+T support operation below 1.0V VCC?

No-MAX6449UT46L+T guarantees valid RESET output logic only down to VCC = 1.0V, as specified in Absolute Maximum Ratings and Electrical Characteristics. Below 1.0V, RESET current-sinking capability degrades significantly, and the output may float. For applications requiring reset assertion down to 0V, a 100kΩ external pulldown resistor is recommended-but only with push-pull versions like MAX6449UT46L+T, not open-drain alternatives.

What package type and dimensions does MAX6449UT46L+T use?

MAX6449UT46L+T uses a 6-pin SOT23 package (package code U6+1, outline 21-0058), measuring 2.9mm × 1.6mm × 1.1mm with 0.95mm lead pitch. It is RoHS-compliant and marked with a top-mark identifier per Maxim's packaging guidelines. The SOT23-6 footprint is compatible with standard pick-and-place equipment and IPC-7351B land patterns (land pattern no. 90-0175).