Analog Devices Inc./Maxim Integrated MAX6449UT16L

Overview

MAX6449UT16L from Maxim Integrated is a dual-supply microprocessor supervisor IC with one fixed-threshold (1.575V) and one adjustable-threshold (0.63V nominal) reset monitor, two delayed manual reset inputs (MR1/MR2), push-pull active-low RESET output, and 6.72s extended setup period - designed for robust system initialization in set-top boxes and industrial equipment.

For engineers reviewing the MAX6449UT16L datasheet, MAX6449UT16L pinout, MAX6449UT16L application, or MAX6449UT16L equivalent, key selection criteria include its dual-monitor architecture, 0.63V RSTIN threshold compatibility with low-voltage rails, guaranteed reset assertion down to VCC = 1.0V, and immunity to <20µs transients at 100mV overdrive.

Technical Context

The MAX6449UT16L implements two independent voltage monitoring paths: VCC is monitored against a factory-trimmed 1.575V threshold (±1.5% accuracy), while RSTIN connects to an external resistor divider to monitor voltages as low as 0.63V with 2.5mV hysteresis. Its dual MR1/MR2 inputs require simultaneous low assertion for 6.72s before generating a 140ms–280ms one-shot reset pulse.

Internal 50kΩ pullups on MR1 and MR2 eliminate external components; the push-pull RESET output sinks up to 3.2mA at VCC ≥ 4.25V and guarantees valid logic down to VCC = 1.0V. The device operates across –40°C to +85°C and consumes only 6µA typical supply current at 3.6V.

Key Specifications

Pinout & Package

MAX6449UT16L is housed in a 6-pin SOT23 package (U6+1 outline), with 0.95mm pitch, 2.9mm × 1.6mm footprint, and exposed pad for thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6449UT16L, MAX6450UT16L offers identical supervision functionality but requires external pullup due to open-drain output, while TPS3808G33DBVR provides lower quiescent current but cannot monitor sub-1V rails or coordinate dual-supply sequencing - making MAX6449UT16L uniquely suited for multi-rail embedded systems demanding precision, flexibility, and noise immunity.

Availability

MAX6449UT16L is available at Aetrix Electronics and suitable for set-top boxes, DVD players, industrial PLCs, automotive infotainment units, and medical diagnostic equipment requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MAX6449UT16L 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, communications, and consumer applications.

The MAX6443–MAX6452 family delivers high-immunity microprocessor supervisors with extended manual reset timing and dual-threshold monitoring - specifically engineered for reliability-critical embedded systems where false resets must be eliminated.

FAQ

What is the exact reset threshold voltage for VCC on the MAX6449UT16L?

The MAX6449UT16L has a factory-set VCC reset threshold of 1.575V, with guaranteed tolerance of ±1.5% (1.52V to 1.62V) over –40°C to +85°C. This value corresponds to the "16" suffix in MAX6449UT16L per Table 1 of the datasheet. The threshold exhibits 60ppm/°C tempco and 2×VTH hysteresis, ensuring stable trip points across temperature.

How does the RSTIN pin function on the MAX6449UT16L, and what voltage range can it monitor?

The RSTIN pin on MAX6449UT16L is a high-impedance input referenced to a precise 0.630V internal comparator threshold (0.610V to 0.650V over temperature). When connected to the center tap of an external resistor divider, it enables monitoring of any supply voltage using VMON-TH = 0.63 × (R1 + R2)/R2 - supporting rails as low as 0.63V or as high as required by resistor selection.

What is the purpose of the dual manual reset inputs (MR1 and MR2) on the MAX6449UT16L?

On MAX6449UT16L, both MR1 and MR2 are active-low inputs with internal 50kΩ pullups to VCC. They require simultaneous assertion for the full 6.72s (L-suffix) extended setup period before generating a 140ms–280ms RESET pulse. This dual-input requirement prevents accidental resets from single-point failures, ESD, or brief switch closures - critical for field-service and safety-critical applications.

Does the MAX6449UT16L support operation down to 1.0V VCC, and what happens to RESET below that?

Yes, MAX6449UT16L guarantees valid RESET output logic down to VCC = 1.0V - meaning it will correctly assert or deassert RESET even during severe brownout. Below 1.0V, current-sinking capability declines rapidly; for applications requiring RESET validity down to 0V, a 100kΩ pulldown resistor must be added to the push-pull RESET output, as specified in the datasheet's "Ensuring a Valid RESET Down to VCC = 0V" section.

What package type and pin configuration does the MAX6449UT16L use?

MAX6449UT16L uses a 6-pin SOT23 package (U6+1 outline) with standard 0.95mm pitch. Pin 1 is GND, Pin 2 is VCC, Pin 3 is MR1, Pin 4 is RESET, Pin 5 is MR2, and Pin 6 is RSTIN - matching the top-view diagram in the datasheet's Pin Configurations section and validated against Maxim's official package drawings.