Analog Devices Inc./Maxim Integrated MAX6445UK16L-T

Overview

MAX6445UK16L-T from Maxim Integrated is a dual-manual-reset, fixed-threshold microprocessor supervisory circuit in 5-pin SOT23 package. It monitors VCC at 1.575V threshold with ±1.5% accuracy, features two extended-setup manual reset inputs (MR1/MR2), 210ms typical reset timeout, and operates from -40°C to +85°C. It prevents nuisance resets in consumer electronics power-on sequencing.

For engineers reviewing the MAX6445UK16L-T datasheet, MAX6445UK16L-T pinout, MAX6445UK16L-T application, or MAX6445UK16L-T equivalent, key selection criteria include its dual extended-setup manual reset architecture, guaranteed reset assertion down to VCC = 1.0V, 6µA supply current, and compatibility with front-panel pushbutton interfaces requiring >6.72s hold time.

Technical Context

The MAX6445UK16L-T implements dual independent manual reset inputs (MR1 and MR2), both requiring simultaneous low assertion for ≥6.72s (L-suffix) before generating a one-shot RESET pulse. Its internal comparators monitor VCC against a factory-trimmed 1.575V threshold with 60ppm/°C tempco and 2×VTH hysteresis.

RESET output is active-low push-pull, sinking 50µA at VCC ≥1.0V with VOL ≤0.3V, and remains valid across full operating voltage (1.0V–5.5V). The device uses BiCMOS process and includes internal 50kΩ pullups on MR1/MR2 pins, eliminating external components for basic operation.

Key Specifications

Pinout & Package

Package: 5-pin SOT23 (U5-1, outline 21-0057), footprint-compatible with standard SOT23-5 land pattern (90-0174).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6445UK16L-T, MAX6446UK16L-T adds open-drain flexibility at cost of extra resistor, while TPS3808G16DBVR trades dual-MR immunity for 3.5× lower supply current - selection depends on whether reset security or standby power dominates design priorities.

Availability

MAX6445UK16L-T is available at Aetrix Electronics and suitable for set-top boxes, DVD players, and DSL modems requiring stable component supply with guaranteed industrial temperature operation and long-term manufacturability.

Supply support for MAX6445UK16L-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 designs precision analog and mixed-signal ICs for power, sensing, and interface applications, serving industrial, communications, and consumer markets.

The MAX6443–MAX6452 family delivers robust microprocessor supervision with extended manual reset setup periods, targeting consumer electronics and industrial equipment where accidental reset must be eliminated.

FAQ

What is the exact reset threshold voltage of the MAX6445UK16L-T?

The MAX6445UK16L-T has a factory-trimmed VCC reset threshold of 1.575V with ±1.5% tolerance over temperature. This value is set by the "16" suffix per Table 1 and is guaranteed across the full -40°C to +85°C operating range with 60ppm/°C tempco and 2×VTH hysteresis. The threshold applies specifically to the VCC pin; no RSTIN functionality is present in this variant.

How does the dual manual reset function work on the MAX6445UK16L-T?

The MAX6445UK16L-T requires both MR1 and MR2 inputs to be held low simultaneously for the full 6.72s (L-suffix) extended setup period before asserting the RESET output. Neither input alone triggers reset - both must meet the timing condition. Internal 50kΩ pullups ensure defined logic states when switches are open, and the dual-input requirement prevents accidental reset from single-point failures or noise on one line.

Is the RESET output of MAX6445UK16L-T push-pull or open-drain?

The MAX6445UK16L-T features an active-low push-pull RESET output, confirmed by the "U" prefix in the package code (U5-1) and ordering table cross-reference. This eliminates the need for an external pullup resistor, unlike the open-drain variant MAX6446UK16L-T. The push-pull output sinks 50µA at VCC ≥1.0V with VOL ≤0.3V and sources current when deasserted per VOH specifications.

What is the minimum VCC voltage at which MAX6445UK16L-T guarantees valid RESET operation?

The MAX6445UK16L-T guarantees correct RESET output logic state down to VCC = 1.0V, as specified in Absolute Maximum Ratings and Electrical Characteristics. Below 1.0V, reset assertion is not guaranteed. This ensures reliable brownout detection and reset assertion during gradual power decay in systems with weak hold-up capacitors or aging power supplies.

Can MAX6445UK16L-T monitor a voltage other than VCC?

No, the MAX6445UK16L-T monitors only the VCC supply pin at its fixed 1.575V threshold. It does not include the RSTIN pin found in MAX6449–MAX6452 variants. For adjustable-threshold monitoring of secondary rails, consider MAX6449UT16L-T or MAX6450UT16L-T, which add a high-impedance RSTIN input with 0.63V reference for external resistor-divider configuration.