Analog Devices Inc./Maxim Integrated MAX6443US31L+T

Overview

MAX6443US31L+T from Maxim Integrated is a single-supply, fixed-threshold microprocessor reset supervisor IC with one extended-setup manual reset input (MR1), active-low push-pull RESET output, 3.075V VCC reset threshold, and 6.72s manual reset setup period. It monitors +3.3V systems in set-top boxes and consumer electronics, asserting a 210ms typical reset pulse after supply recovery or MR1 activation.

For engineers reviewing the MAX6443US31L+T datasheet, MAX6443US31L+T pinout, MAX6443US31L+T application, or MAX6443US31L+T equivalent, key selection criteria include guaranteed reset validity down to VCC = 1.0V, immunity to <20µs transients at 100mV overdrive, low 6µA supply current, and SOT143-4 package compatibility with space-constrained industrial and automotive designs.

Technical Context

The MAX6443US31L+T implements a precision bandgap-based voltage monitor for VCC with factory-trimmed 3.075V threshold (±1.5% over -40°C to +85°C) and 60ppm/°C tempco. Its internal timing circuit enforces a fixed 6.72s MR1 low-hold requirement before generating a one-shot RESET pulse.

RESET assertion is synchronized to VCC or MR1 events: VCC falling below 3.075V triggers a 20µs delay before RESET goes low; MR1 held low ≥6.72s initiates a 140ms minimum timeout pulse. The push-pull output drives loads directly without external pullup, sinking 50µA at VCC ≥1.0V with VOL ≤0.3V.

Key Specifications

Pinout & Package

MAX6443US31L+T is housed in a 4-pin SOT143 package (U4+1 outline, 21-0052) with gull-wing leads, 1.3mm × 1.3mm footprint, and 0.95mm height - optimized for high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6444US31L+T, the MAX6443US31L+T's push-pull output simplifies design by removing pullup resistors; versus TPS3808G33DBVR, it adds critical 6.72s debounced manual reset for field-service recovery - essential in consumer CE devices where front-panel reliability is paramount.

Availability

MAX6443US31L+T is available at Aetrix Electronics and suitable for set-top boxes, DVD players, and cable modems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6443US31L+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 industrial, communications, and consumer markets with emphasis on power efficiency and reliability.

The MAX6443–MAX6452 family delivers ultra-low-power microprocessor supervision with extended manual reset timing for consumer electronics and industrial equipment where nuisance reset immunity is critical.

FAQ

What is the exact reset threshold voltage of the MAX6443US31L+T?

The MAX6443US31L+T has a factory-trimmed VCC reset threshold of 3.075V, specified with ±1.5% tolerance over the full -40°C to +85°C operating range. This value is confirmed in Table 1 of the datasheet under suffix "31", and applies directly to the MAX6443US31L+T without adjustment or external components.

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

The MAX6443US31L+T requires MR1 to be held low for a minimum of 6.72 seconds before asserting RESET - a duration far exceeding typical mechanical switch bounce or accidental presses. This ensures only intentional user actions trigger hard reset, while shorter closures (e.g., <1s) are ignored, preserving system stability during normal front-panel interaction.

Can the MAX6443US31L+T operate reliably when VCC drops below 1.5V?

Yes - the MAX6443US31L+T guarantees valid RESET assertion down to VCC = 1.0V, with VOL ≤0.3V when sinking 50µA. Its internal circuitry remains functional and accurate throughout this range, making it suitable for brownout detection in systems with unregulated or decaying supplies where other supervisors fail.

What package type and pin count does the MAX6443US31L+T use?

The MAX6443US31L+T uses a 4-pin SOT143 package (outline 21-0052), with pins arranged as GND (1), RESET (2), MR1 (3), and VCC (4) in top-view orientation. This compact 1.3mm × 1.3mm footprint supports high-density PCB layouts in consumer electronics and industrial control panels.

Is the RESET output of the MAX6443US31L+T push-pull or open-drain?

The MAX6443US31L+T features an active-low push-pull RESET output, eliminating the need for an external pullup resistor. It actively drives low (VOL ≤0.3V at 50µA) and high (VOH ≥0.8×VCC) - unlike open-drain variants such as MAX6444US31L+T, which require external pullup for logic-high assertion.