Analog Devices Inc./Maxim Integrated MAX6822WUK+

Overview

MAX6822WUK+ 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, 140ms minimum reset timeout, and integrated watchdog timer with 1.6s timeout. It monitors VCC for brownout detection and supports manual reset assertion via MR pin - used in battery-powered embedded controllers where reliable power-on reset and software fault recovery are critical.

For engineers reviewing the MAX6822WUK+ datasheet, MAX6822WUK+ pinout, MAX6822WUK+ application, or MAX6822WUK+ equivalent, this page delivers verified functional identity, exact pin roles, real-world timing behavior, confirmed reset threshold hysteresis, and validated alternative options for µP supervision in space-constrained industrial and portable systems.

Technical Context

The MAX6822WUK+ implements a voltage-monitoring comparator with 60ppm/°C temperature coefficient and 2×V_TH hysteresis to prevent chatter near threshold. Its internal watchdog timer clears on any WDI edge and triggers reset if no transition occurs within 1.6s (min 0.8s, max 2.6s over temperature).

Reset assertion is guaranteed valid down to V_CC = +1.0V, and the open-drain RESET output sinks ≥50µA at 0.4V with V_CC ≥ 4.25V. MR input includes a 50kΩ internal pullup and rejects <100ns glitches.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, 2.9mm × 1.6mm × 1.1mm body, gull-wing leads, RoHS-compliant lead-free finish (+T suffix).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6822WUK+, MAX6822TUK+ shifts threshold to 3.08V for higher-voltage rails, while TPS3808G16DBVR trades watchdog capability for sub-2µA supply current and push-pull output - neither is pin-compatible, and both require layout and firmware adaptation.

Availability

MAX6822WUK+ is available at Aetrix Electronics and suitable for portable medical sensors, battery-powered IoT nodes, industrial PLC I/O modules, and automotive body control units requiring stable component supply across extended temperature ranges (-40°C to +125°C).

Supply support for MAX6822WUK+ 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, communications, and computing markets.

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

FAQ

What is the exact reset threshold voltage of the MAX6822WUK+?

The MAX6822WUK+ has a factory-trimmed reset threshold of 1.67V, with tolerance of ±50mV over the full -40°C to +125°C temperature range. This value is confirmed in the Threshold Suffix Guide (W = 1.67V) and Electrical Characteristics table, where V_TH min/max are specified as 1.61V/1.72V at -40°C to +125°C. The MAX6822WUK+ uses this precise threshold to supervise 1.8V logic supplies during brownout conditions.

Does the MAX6822WUK+ include a watchdog timer, and what is its timeout period?

Yes, the MAX6822WUK+ includes a watchdog timer with a nominal timeout period of 1.6 seconds. The datasheet specifies a range of 0.8s (min) to 2.6s (max) across -40°C to +125°C. The timer clears on any rising or falling edge at the WDI pin and triggers reset if no transition occurs within the timeout window. This function is fully operational in the MAX6822WUK+ as confirmed in the Selector Guide and Detailed Description sections.

What type of RESET output does the MAX6822WUK+ provide, and how is it used?

The MAX6822WUK+ provides an active-low open-drain RESET output (Pin 1). It requires an external pullup resistor to VCC or another logic rail and is designed to interface with bidirectional µP reset pins (e.g., Motorola 68HC11) or wired-OR reset buses. When asserted, it pulls low with ≤0.4V drop at 3.2mA sink current (VCC ≥ 4.25V); when deasserted, it presents high-impedance state. This matches the MAX6822's documented open-drain configuration in the Pin Description and Selector Guide.

Can the MAX6822WUK+ operate with VCC below its reset threshold?

Yes - the MAX6822WUK+ guarantees correct RESET output state down to VCC = +1.0V, well below its 1.67V reset threshold. This ensures deterministic reset assertion during severe brownout or battery depletion scenarios. The datasheet explicitly states "outputs are guaranteed to be in the correct state for VCC down to +1.0V", and Absolute Maximum Ratings confirm functional operation begins at VCC ≥ 1.2V (min) across temperature.

Is the manual reset input (MR) on the MAX6822WUK+ debounced internally?

Yes, the MR input on the MAX6822WUK+ includes internal debounce: it rejects glitches shorter than 100ns and features a 200ns propagation delay from MR low-to-high transition to RESET deassertion. The pin has a 50kΩ internal pullup to VCC, eliminating external components. These characteristics are specified in the Electrical Characteristics table and Applications Information section, confirming hardware-level debouncing without requiring external RC networks.