Analog Devices Inc./Maxim Integrated MAX6822WUK+T

Overview

MAX6822WUK+T from Maxim Integrated is a low-voltage microprocessor supervisory IC in SOT23-5 package, featuring open-drain active-low RESET output, 1.67V reset threshold (W suffix), 140ms minimum reset timeout, and 1.6s watchdog timer. It monitors VCC down to +1.0V and supports manual reset input for reliable power-up, brownout, and software fault recovery in embedded controllers and portable equipment.

For engineers reviewing the MAX6822WUK+T datasheet, MAX6822WUK+T pinout, MAX6822WUK+T application, or MAX6822WUK+T equivalent, key selection criteria include its 1.67V threshold accuracy over –40°C to +125°C, guaranteed reset validity at VCC = +1.0V, open-drain RESET compatibility with bidirectional µP reset pins, and integrated watchdog with 50ns pulse detection capability.

Technical Context

The MAX6822WUK+T implements a precision bandgap-based voltage monitor with 60ppm/°C temperature coefficient and 2×VTH hysteresis to prevent chatter during threshold crossings. Its internal watchdog timer resets on WDI edge transitions and clears automatically during asserted reset or MR activation.

This device uses BiCMOS process (750 transistors) and features an internal 50kΩ MR pullup resistor, enabling direct connection of a momentary switch to GND without external components. The open-drain RESET output requires an external pullup and supports wired-OR configurations with other reset sources.

Key Specifications

Pinout & Package

MAX6822WUK+T is housed in a RoHS-compliant 5-pin SOT23-5 package (U5-1 outline, 21-0057 land pattern), measuring 2.9mm × 1.6mm × 1.1mm, suitable for high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6822WUK+T, MAX6822TUK+T offers identical functionality but targets higher-voltage rails, while TPS3808G16DBVR reduces feature set to lower cost and quiescent current-but sacrifices critical watchdog and manual reset capabilities required for autonomous embedded recovery.

Availability

MAX6822WUK+T is available at Aetrix Electronics and suitable for set-top boxes, portable/battery-powered equipment, and embedded controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6822WUK+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, automotive, and computing applications.

The MAX6821–MAX6825 family delivers compact, low-power µP supervision with integrated watchdog and manual reset-engineered specifically for space-constrained, battery-sensitive, and high-reliability embedded systems.

FAQ

What is the exact reset threshold voltage of the MAX6822WUK+T and how is it specified across temperature?

The MAX6822WUK+T has a nominal reset threshold of 1.67V, with tolerance of ±30mV over the full operating range of –40°C to +125°C. Electrical Characteristics specify min/max values of 1.61V/1.72V at –40°C to +125°C, and 1.62V/1.71V at –40°C to +85°C. Its 60ppm/°C temperature coefficient ensures predictable drift, critical for battery-powered devices experiencing ambient thermal swings.

Does the MAX6822WUK+T support manual reset functionality, and how is the MR pin configured?

Yes, the MAX6822WUK+T includes a manual reset (MR) input on Pin 3. It is active-low with an internal 50kΩ pullup resistor to VCC, allowing direct connection of a momentary switch to GND-no external components needed. When MR is pulled low, reset asserts immediately and remains active for the full 140ms timeout after MR returns high, providing hardware-initiated recovery independent of VCC or watchdog state.

What type of RESET output does the MAX6822WUK+T provide, and what design implications does that have?

The MAX6822WUK+T provides an open-drain active-low RESET output on Pin 1. This requires an external pullup resistor and enables wired-OR connection with other reset sources (e.g., power-on reset ICs or FPGA reset outputs). It also interfaces directly with microcontrollers having bidirectional reset pins (e.g., Motorola 68HC11), where either device can assert reset-making MAX6822WUK+T ideal for multi-source reset architectures.

How does the watchdog timer in the MAX6822WUK+T operate, and what is its timeout period?

The MAX6822WUK+T watchdog timer has a nominal timeout period of 1.6 seconds, with min/max values of 0.80s/2.60s over –40°C to +125°C. It triggers reset if the WDI pin (Pin 4) remains static-neither rising nor falling-for longer than this interval. The timer clears on any WDI edge transition, MR assertion, or active RESET, and detects pulses as short as 50ns, ensuring robust detection of firmware stalls without false triggers from noise.

Can the MAX6822WUK+T operate reliably at very low supply voltages, and what is its minimum functional VCC?

Yes, the MAX6822WUK+T guarantees correct reset output state down to VCC = +1.0V, as confirmed in the Electrical Characteristics table. This allows it to assert reset even during severe brownout or battery depletion scenarios where VCC drops below typical 1.2V logic thresholds-ensuring deterministic system recovery where other supervisors may fail silently or behave unpredictably.