Analog Devices Inc./Maxim Integrated MAX6822ZUK

Overview

MAX6822ZUK from Maxim Integrated is a low-voltage microprocessor supervisory IC in SOT23-5 package, providing open-drain active-low RESET output, 2.32V reset threshold (Z suffix), 140ms minimum reset timeout, and 1.6s watchdog timeout. It monitors VCC for brownout detection, accepts manual reset via MR pin, and asserts reset during power-up, power-down, or software fault conditions - commonly used in portable battery-powered equipment and embedded controllers.

For engineers reviewing the MAX6822ZUK datasheet, MAX6822ZUK pinout, MAX6822ZUK application, or MAX6822ZUK equivalent, this device serves as a precision voltage monitor with integrated watchdog and manual reset for reliable µP startup and runtime supervision in space-constrained, low-power systems.

Technical Context

The MAX6822ZUK implements a precision bandgap-based voltage reference to detect VCC falling below 2.32V ±1.5% over -40°C to +125°C, with 60ppm/°C temperature coefficient and 2×VTH hysteresis. Its internal reset timer guarantees ≥140ms assertion after VCC recovery, while the watchdog circuit triggers reset if WDI remains static beyond 1.6s (min 0.8s, max 2.6s).

It features an open-drain RESET output capable of sinking 3.2mA at VCC ≥4.25V with VOL ≤0.4V, and supports VCC operation down to +1.0V with guaranteed reset validity. The MR input includes a 50kΩ internal pullup and rejects <100ns glitches, enabling direct switch connection without external debounce.

Key Specifications

Pinout & Package

Package: SOT23-5 (5-pin surface-mount, 2.9mm × 1.6mm × 1.1mm body, JEDEC MO-178AA compliant).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6822TUK, MAX6822ZUK enables lower-voltage system supervision with identical timing and interface; compared with MAX6315US23D3+, it adds watchdog and manual reset functionality at the cost of slightly higher quiescent current.

Availability

MAX6822ZUK is available at Aetrix Electronics and suitable for portable/battery-powered equipment, embedded controllers, set-top boxes, and automotive systems requiring stable component supply across industrial temperature ranges.

Supply support for MAX6822ZUK 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.

The MAX6821–MAX6825 product line delivers compact, low-voltage µP supervisors targeting space- and power-constrained embedded systems needing coordinated reset, watchdog, and manual intervention capabilities.

FAQ

What is the exact reset threshold voltage of MAX6822ZUK and its tolerance?

The MAX6822ZUK has a factory-trimmed reset threshold of 2.32V with ±1.5% tolerance over the full -40°C to +125°C temperature range. This value is specified in the Threshold Suffix Guide and confirmed in the Electrical Characteristics table under VTH for MAX682_Z. The device guarantees correct reset assertion when VCC falls below this threshold and holds reset for ≥140ms after VCC rises above it.

Does MAX6822ZUK support operation down to 1.0V VCC, and what does that mean for system design?

Yes, MAX6822ZUK guarantees valid reset output behavior down to VCC = +1.0V, meaning the internal circuitry remains functional and the RESET signal retains correct logic state even during severe brownout. This allows safe µP hold-down in ultra-low-power or battery-depleted states where other supervisors may release reset prematurely - a key requirement for data retention and controlled shutdown in portable equipment.

How does the watchdog timer in MAX6822ZUK interact with the manual reset input (MR)?

In MAX6822ZUK, asserting MR low immediately triggers reset and clears the watchdog timer; reset remains active for the full 140ms timeout period after MR returns high. The watchdog timer is also cleared whenever RESET is asserted (by any cause) or WDI receives a rising/falling edge. Thus, MR and WDI operate independently but share the same reset generation path and timeout duration - no priority arbitration is needed.

Can MAX6822ZUK's open-drain RESET output drive multiple devices on a shared reset bus?

Yes, MAX6822ZUK's open-drain RESET output is explicitly designed for wired-OR configurations. When used with a single external pullup resistor, it can share a common reset bus with other open-drain or open-collector reset sources (e.g., power supply sequencers, other supervisors). This enables coordinated system-wide reset assertion without contention - a standard practice in complex embedded systems requiring multi-chip initialization synchronization.

What is the maximum allowable leakage current on the WDI pin when disabled, and how should it be handled?

When the watchdog is disabled (WDI left floating or driven high-Z), MAX6822ZUK specifies a maximum WDI leakage current of 10µA and maximum load capacitance of 200pF. To ensure reliable disablement, connect WDI directly to VCC or GND only if drive strength permits; otherwise, leave it unconnected with proper PCB layout (short trace, no stubs) and avoid routing near noise sources. Do not add series resistance unless validated per application note.