Analog Devices Inc./Maxim Integrated MAX6444US29L+T

Overview

MAX6444US29L+T from Maxim Integrated is a single-supply, fixed-threshold microprocessor reset supervisor IC with active-low open-drain RESET output, 2.925V reset threshold (±0.075V), 6.72s extended manual reset setup period (tMR), and guaranteed operation down to VCC = 1.0V. It monitors +3.3V systems in consumer electronics and industrial equipment where nuisance resets from brief switch closures must be avoided.

For engineers reviewing the MAX6444US29L+T datasheet, MAX6444US29L+T pinout, MAX6444US29L+T application, or MAX6444US29L+T equivalent, key selection criteria include its precise 2.925V VTH, 6.72s MR1 setup timeout, 140ms min reset timeout, 6µA supply current, and SOT143-4 package compatibility with space-constrained PCB layouts.

Technical Context

The MAX6444US29L+T implements a precision bandgap-based voltage monitor for VCC with factory-trimmed 2.925V threshold and 60ppm/°C tempco. Its internal timing circuit enforces a fixed 6.72s low assertion on MR1 before generating a one-shot 140ms–280ms RESET pulse.

It features an open-drain RESET output with ≤0.4V VOL at 3.2mA sink, guaranteed valid logic state for VCC ≥ 1.0V, and immunity to transients ≤20µs when VCC dips 100mV below threshold - enabling robust front-panel reset implementation without external debouncing.

Key Specifications

Pinout & Package

SOT143-4 package: 1.3mm × 2.1mm body, 0.95mm pitch, lead(Pb)-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6444US29L+T, MAX6316LUK29D3+T offers faster manual reset activation but lacks nuisance-reset immunity, while TPS3808G18DBVR reduces current consumption by 60% but requires external components and cannot replace the 6.72s deliberate-reset function.

Availability

MAX6444US29L+T is available at Aetrix Electronics and suitable for set-top boxes, DVD players, and cable modems requiring stable component supply with guaranteed automotive-grade temperature performance (-40°C to +85°C).

Supply support for MAX6444US29L+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 applications.

The MAX6443–MAX6452 family delivers highly reliable, low-power microprocessor supervisors optimized for systems where mechanical switch-induced false resets must be eliminated through extended manual reset timing.

FAQ

What is the exact reset threshold voltage for MAX6444US29L+T?

The MAX6444US29L+T has a factory-trimmed VCC reset threshold of 2.925V, with guaranteed limits of 2.85V (min) and 3.00V (max) over the full -40°C to +85°C temperature range. This value is confirmed in the Electrical Characteristics table under "VCC Reset Threshold" for suffix "29", and applies specifically to the MAX6444US29L+T - not the broader MAX6444 family.

How does the 6.72s manual reset setup period work on MAX6444US29L+T?

The MAX6444US29L+T requires MR1 to be held low for ≥6.72s (typical) before asserting RESET - a feature implemented via internal RC timing to reject short switch closures. Once triggered, RESET pulses low for ≥140ms. The "L" suffix in MAX6444US29L+T explicitly denotes this 6.72s setup period, per Table 2 in the datasheet.

Can MAX6444US29L+T monitor voltages other than VCC?

No - the MAX6444US29L+T monitors only the VCC supply pin. It lacks RSTIN functionality (which appears only in MAX6449–MAX6452 variants). For adjustable-threshold monitoring of secondary rails, consider MAX6449US29L+T instead; MAX6444US29L+T is strictly a single-fixed-threshold VCC supervisor.

What is the RESET output configuration of MAX6444US29L+T?

The MAX6444US29L+T features an active-low open-drain RESET output, as confirmed in the Ordering Information table and Pin Description section. It requires an external pullup resistor (≥20kΩ to VCC) to generate a high-level signal. Push-pull variants exist in the family (e.g., MAX6443), but MAX6444US29L+T is exclusively open-drain.

Is MAX6444US29L+T qualified for automotive applications?

No - MAX6444US29L+T is rated for the extended industrial temperature range (-40°C to +85°C) but is not AEC-Q100 qualified. Automotive-grade versions carry the "/V" suffix (e.g., MAX6444US16K/V+T). The "V" designation is absent in MAX6444US29L+T, confirming its industrial-only qualification.