Analog Devices Inc./Maxim Integrated MAX6443US31L

Overview

MAX6443US31L from Maxim Integrated is a single-supply, fixed-threshold microprocessor reset supervisor IC with one extended-setup manual reset input (MR1), 3.075V VCC reset threshold, and 6.72s manual reset setup period. It delivers active-low push-pull RESET output, 210ms typical timeout, 6µA supply current, and guaranteed operation down to VCC = 1.0V - used in set-top boxes and consumer electronics for reliable power-on reset and nuisance-reset immunity.

For engineers reviewing the MAX6443US31L datasheet, MAX6443US31L pinout, MAX6443US31L application, or MAX6443US31L equivalent, this page provides verified technical context, pin-level design meaning, real-world use scenarios, and validated alternative options for industrial and consumer embedded systems requiring stable brownout detection and long-debounce manual reset functionality.

Technical Context

The MAX6443US31L implements a precision bandgap-based voltage monitor for VCC with factory-trimmed 3.075V reset threshold (±1.5% over temperature), 60ppm/°C tempco, and 2×VTH hysteresis. Its internal timing circuit enforces a fixed 6.72s low assertion on MR1 before generating a one-shot 140ms–280ms RESET pulse.

It features a push-pull RESET output capable of sinking 1.2mA at VCC ≥ 2.55V (VOL ≤ 0.3V) and sourcing 200µA at VCC ≥ 1.8V (VOH ≥ 0.8×VCC), with guaranteed valid logic states across the full –40°C to +85°C range and down to VCC = 1.0V.

Key Specifications

Pinout & Package

MAX6443US31L is housed in a 4-pin SOT143 package (pin pitch 0.95mm, body size 2.9mm × 1.3mm), rated for –40°C to +85°C operation and RoHS-compliant (lead-free).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6443US31L, MAX6316US31D offers identical threshold and package but trades push-pull simplicity for open-drain flexibility and reduced debounce time, while TPS3808G33DBVR removes manual reset entirely to achieve lower quiescent current and smaller footprint - making each alternative optimal only when those specific trade-offs align with system architecture constraints.

Availability

MAX6443US31L is available at Aetrix Electronics and suitable for set-top boxes, DVD players, and cable modems requiring stable component supply, long-term lifecycle support, and guaranteed automotive-grade reliability margins.

Supply support for MAX6443US31L 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 in industrial, medical, and consumer systems.

The MAX6443–MAX6452 family was engineered specifically for robust microprocessor supervision in cost-sensitive consumer electronics, emphasizing nuisance-reset immunity, ultra-low ICC, and simplified layout via integrated pullups and push-pull outputs.

FAQ

What is the exact reset threshold voltage of MAX6443US31L?

The MAX6443US31L has a factory-trimmed VCC reset threshold of 3.075V, with ±1.5% tolerance over the full –40°C to +85°C temperature range and 60ppm/°C tempco. This value is defined by the "31" suffix per Table 1 in the datasheet and is laser-trimmed during production to ensure accuracy without external calibration.

How does the 6.72s manual reset setup period prevent nuisance resets in MAX6443US31L?

The MAX6443US31L requires MR1 to remain low for a minimum of 6.72s (typical) before asserting RESET - far exceeding typical mechanical switch bounce duration (<10ms) or accidental button taps. This ensures only deliberate, sustained user action triggers a hard reset, eliminating spurious reboots during normal front-panel interaction.

Can MAX6443US31L operate reliably when VCC drops below 1.8V?

Yes. The MAX6443US31L guarantees valid RESET output logic states down to VCC = 1.0V, including VOL ≤ 0.3V when sinking 1.2mA and VOH ≥ 0.8×VCC when sourcing 200µA. This ensures deterministic reset behavior during deep brownout conditions where many competing supervisors fail.

What is the function of the MR1 pin on MAX6443US31L?

MR1 is an active-low manual reset input with internal 50kΩ pullup to VCC. When pulled low for ≥6.72s, it triggers a one-shot active-low RESET pulse lasting ≥140ms. It is internally debounced and requires no external RC filtering - enabling direct connection to momentary switches in consumer devices.

Does MAX6443US31L require an external pullup resistor on the RESET pin?

No. The MAX6443US31L features a push-pull RESET output, which actively drives both high and low states. Unlike open-drain variants, it does not require an external pullup resistor - simplifying schematic design and reducing BOM count for direct interface to microprocessor reset inputs.