Analog Devices Inc./Maxim Integrated MAX6446UK26L+T

Overview

MAX6446UK26L+T from Maxim Integrated is a dual-manual-reset, fixed-threshold microprocessor supervisor IC with active-low open-drain RESET output. It monitors a single supply (VCC) at 2.625V ±1.5%, features two extended-setup manual reset inputs (MR1 and MR2), asserts RESET for ≥140ms after valid reset conditions, and operates over –40°C to +85°C in a 5-pin SOT23 package. It is used in set-top boxes and cable modems to prevent nuisance resets from front-panel button presses.

For engineers reviewing the MAX6446UK26L+T datasheet, MAX6446UK26L+T pinout, MAX6446UK26L+T application, or MAX6446UK26L+T equivalent, key selection criteria include its 2.625V VCC reset threshold, 6.72s dual-input manual reset setup period (L suffix), 5-pin SOT23 package, open-drain RESET logic, and immunity to transients <20µs at 100mV overdrive.

Technical Context

The MAX6446UK26L+T implements dual extended-setup manual reset logic requiring simultaneous low assertion of both MR1 and MR2 for ≥6.72s before generating a one-shot RESET pulse. Its internal 50kΩ pullup on each MR input enables direct connection to mechanical switches without external components.

It uses a precision bandgap-based voltage comparator to monitor VCC against a factory-trimmed 2.625V threshold with 60ppm/°C tempco and 2×VTH hysteresis. RESET remains asserted for 210ms (typ) after VCC recovers above threshold, ensuring stable processor initialization during brownout recovery.

Key Specifications

Pinout & Package

MAX6446UK26L+T is housed in a 5-pin SOT23 package (package code U5+1), with 0.95mm pitch, 2.9mm × 1.6mm footprint, and exposed pad for thermal performance. Pin 1 is GND, pin 2 is VCC, pin 3 is MR1, pin 4 is RESET, and pin 5 is MR2.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6445UK26L+T, MAX6446UK26L+T provides open-drain flexibility for mixed-voltage systems; compared with TPS3808G33DBVR, it delivers stricter nuisance immunity via dual extended-setup MR inputs and tighter threshold accuracy for 2.5V rails.

Availability

MAX6446UK26L+T is available at Aetrix Electronics and suitable for set-top boxes, cable modems, DVD players, and industrial HMIs requiring stable component supply with guaranteed -40°C to +85°C operation and long-term production support.

Supply support for MAX6446UK26L+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, sensing, and interface applications in industrial, communications, and consumer markets.

The MAX6443–MAX6452 family delivers robust µP supervision with extended manual reset setup periods, targeting consumer electronics and industrial equipment where front-panel reliability and brownout immunity are critical.

FAQ

What is the exact reset threshold voltage of the MAX6446UK26L+T?

The MAX6446UK26L+T has a factory-trimmed VCC reset threshold of 2.625V, with ±1.5% tolerance over temperature. This value is defined by the "26" suffix per Table 1 in the datasheet and is optimized for monitoring 2.5V nominal supply rails in consumer electronics.

How does the dual manual reset function work on the MAX6446UK26L+T?

The MAX6446UK26L+T requires both MR1 and MR2 inputs to be held low simultaneously for the full 6.72s (L suffix) extended setup period before asserting RESET. Neither input alone triggers reset; this dual-input requirement prevents accidental activation from single-switch closures in set-top box or modem front panels.

What package type and pin count does the MAX6446UK26L+T use?

The MAX6446UK26L+T uses a 5-pin SOT23 package (package code U5+1), with standard 0.95mm lead pitch and 2.9mm × 1.6mm body size. Pin 1 is GND, pin 2 is VCC, pin 3 is MR1, pin 4 is RESET, and pin 5 is MR2 - verified from the Pin Configurations section of the datasheet.

Does the MAX6446UK26L+T support open-drain or push-pull RESET output?

The MAX6446UK26L+T features an open-drain RESET output, as confirmed by the Ordering Information table and Pin Description. It requires an external pullup resistor (minimum 20kΩ to VCC) and supports level-shifting to different logic voltages, unlike the push-pull variant MAX6445UK26L+T.

What is the minimum reset timeout period specified for the MAX6446UK26L+T?

The MAX6446UK26L+T guarantees a minimum reset timeout period of 140ms, with a typical value of 210ms. This duration ensures compatibility with microprocessor reset timing requirements, including ARM Cortex-M series and common ASIC boot ROMs that mandate ≥100ms reset assertion.