Analog Devices Inc./Maxim Integrated MAX6446UK16L+T

Overview

MAX6446UK16L+T from Maxim Integrated is a dual-input, fixed-threshold microprocessor supervisor IC with active-low open-drain RESET output, 1.575V VCC reset threshold, and 6.72s extended manual reset setup period (tMR). It monitors a single supply (VCC) and features two active-low manual reset inputs (MR1, MR2), both requiring simultaneous low assertion for ≥6.72s to trigger a 140ms min one-shot reset pulse. Used in set-top boxes and cable modems for robust power-on and service-reset control.

For engineers reviewing the MAX6446UK16L+T datasheet, MAX6446UK16L+T pinout, MAX6446UK16L+T application, or MAX6446UK16L+T equivalent, key selection criteria include its dual extended-setup manual reset architecture, guaranteed reset validity down to VCC = 1.0V, 6µA typical supply current, and SOT23-5 package compatibility with space-constrained consumer electronics designs.

Technical Context

The MAX6446UK16L+T implements a precision voltage monitor with factory-set 1.575V reset threshold (±1.5% over -40°C to +85°C) and 60ppm/°C tempco. Its dual manual reset inputs (MR1, MR2) require concurrent low assertion for the full 6.72s tMR to avoid nuisance resets - a timing-based debouncing mechanism eliminating need for external RC filters.

RESET asserts as an open-drain output with ≤0.4V VOL at 3.2mA sink, requiring a minimum 20kΩ pullup to VCC. The device guarantees valid reset logic down to VCC = 1.0V and consumes only 6µA at 3.6V, enabling battery-backed or ultra-low-power applications where supply stability must be verified before processor initialization.

Key Specifications

Pinout & Package

MAX6446UK16L+T is housed in a 5-pin SOT23 package (package code U5+1, outline 21-0057), with exposed pad not electrically connected. Pin 1 is GND, pin 2 is VCC, pin 3 is MR1, pin 4 is RESET, and pin 5 is MR2 - all pins support -0.3V to +6V absolute max ratings.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6445UK16L+T, the MAX6446UK16L+T adds MR2 for enhanced reset security; versus TPS3808G16DBVR, it trades lower quiescent current for deterministic dual-input timing control - critical in consumer UIs where accidental resets degrade user experience.

Availability

MAX6446UK16L+T is available at Aetrix Electronics and suitable for set-top boxes, cable modems, DVD players, and industrial HMIs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6446UK16L+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, with emphasis on reliability and integration for demanding environments.

The MAX6443–MAX6452 family delivers robust µP supervision with extended manual reset timing, targeting consumer electronics and industrial systems where immunity to nuisance resets is essential for user experience and field reliability.

FAQ

What is the exact reset threshold voltage of the MAX6446UK16L+T?

The MAX6446UK16L+T has a factory-set VCC reset threshold of 1.575V, with guaranteed tolerance of ±1.5% over the full operating temperature range (-40°C to +85°C). This value is laser-trimmed during production and documented in the Electrical Characteristics table under "VCC Reset Threshold" with suffix "16". The threshold remains stable with 60ppm/°C tempco, ensuring consistent brownout detection across thermal environments.

How does the dual manual reset function work on the MAX6446UK16L+T?

The MAX6446UK16L+T requires both MR1 and MR2 inputs to be held low simultaneously for the full 6.72s extended setup period (tMR) before asserting RESET. Neither input alone triggers reset - this dual-input requirement prevents accidental activation from single-switch bounce or EMI. Once both are low for ≥6.72s, RESET pulses low for ≥140ms. Both inputs feature 50kΩ internal pullups to VCC, simplifying front-panel switch interfacing.

What is the recommended pullup resistor value for the open-drain RESET output of the MAX6446UK16L+T?

A minimum 20kΩ pullup resistor to VCC is specified for the open-drain RESET output of the MAX6446UK16L+T. For 3.3V systems, a 47kΩ resistor is commonly used to limit current while ensuring fast rise time. The resistor must be placed externally - no internal pullup exists. At VCC ≥4.25V, the output can sink up to 3.2mA while maintaining VOL ≤0.4V, so the pullup value should be selected to keep sink current within this limit under worst-case VCC and load conditions.

Can the MAX6446UK16L+T operate reliably at VCC = 1.0V?

Yes, the MAX6446UK16L+T guarantees valid RESET output logic down to VCC = 1.0V - meaning it will correctly assert or deassert the open-drain RESET signal even when supply voltage drops to this level. Below 1.0V, reset behavior is not guaranteed. This specification ensures deterministic microprocessor reset during deep brownout conditions common in battery-powered or unregulated supply applications, where other supervisors may fail to hold reset state.

What package type and pin count does the MAX6446UK16L+T use?

The MAX6446UK16L+T uses a 5-pin SOT23 package (package code U5+1, outline 21-0057), with pin 1 = GND, pin 2 = VCC, pin 3 = MR1, pin 4 = RESET, and pin 5 = MR2. It is supplied in tape-and-reel format (2500-piece minimum order quantity) and is lead(Pb)-free compliant. The compact 2.9mm × 1.6mm footprint supports high-density PCB layouts and automated pick-and-place assembly.