Analog Devices Inc./Maxim Integrated MAX6821YUK-T

Overview

MAX6821YUK-T from Maxim Integrated is a low-voltage microprocessor supervisory IC in 5-pin SOT23 package, providing voltage monitoring (2.19V threshold), 140ms minimum reset timeout, 1.6s watchdog timer, manual reset input, and push-pull active-low RESET output. It ensures reliable µP startup and brownout recovery in portable/battery-powered equipment and embedded controllers.

For engineers reviewing the MAX6821YUK-T datasheet, MAX6821YUK-T pinout, MAX6821YUK-T application, or MAX6821YUK-T equivalent, this page delivers verified functional identity, exact pin roles, confirmed reset timing behavior, validated watchdog interaction with WDI, and real-world selection guidance for critical µP monitoring designs.

Technical Context

The MAX6821YUK-T integrates a precision voltage detector with ±1.5% threshold accuracy at 2.19V over –40°C to +125°C, a monostable reset generator with guaranteed 140ms–320ms timeout, and a watchdog timer that triggers reset if WDI remains static beyond 1.12s–2.60s. Its internal 50kΩ MR pullup enables direct switch-to-GND connection without external components.

RESET asserts low when VCC falls below 2.19V, MR is pulled low, or WDI fails to toggle; it remains asserted for the full timeout after recovery. The push-pull output drives low to ≤0.3V at 50µA (VCC ≥ 1.0V) and high to ≥0.8×VCC at 200µA (VCC ≥ 1.8V), ensuring robust interface with µP reset inputs across its 1.2V–5.5V operating range.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5 (U5-1 outline), footprint compatible with industry-standard 0.95mm pitch land pattern (Maxim land pattern no. 21-0057).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6821YUK-T, MAX6326YUT+T reduces functionality to basic reset generation-lower cost but no watchdog safety net; TPS3808G18DBVR offers wider VCC range but sacrifices MR flexibility and adds external component dependency, impacting reliability in portable designs.

Availability

MAX6821YUK-T is available at Aetrix Electronics and suitable for portable/battery-powered equipment, embedded controllers, intelligent instruments, and critical µP monitoring applications requiring stable component supply across industrial temperature ranges.

Supply support for MAX6821YUK-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 demanding industrial, medical, and communications applications.

The MAX6821YUK-T belongs to the MAX682x family of low-voltage µP supervisors engineered specifically for reliable power-up sequencing, brownout protection, and runtime fault detection in space-constrained embedded systems.

FAQ

What is the exact reset threshold voltage of the MAX6821YUK-T?

The MAX6821YUK-T has a factory-trimmed reset threshold of 2.19V, with ±1.5% accuracy over the full –40°C to +125°C temperature range. This value is fixed by the "Y" suffix and is guaranteed in production testing per Maxim's Electrical Characteristics table. The threshold is referenced to the VCC pin and remains stable across operating voltage variations, making the MAX6821YUK-T suitable for monitoring 2.2V supply rails in battery-powered systems.

Does the MAX6821YUK-T include a watchdog timer, and what is its timeout behavior?

Yes, the MAX6821YUK-T includes a watchdog timer with a nominal timeout period of 1.6 seconds. Over temperature, the timeout ranges from 0.80s to 2.60s. The timer resets on any rising or falling edge at the WDI pin and triggers a full reset timeout if WDI remains static beyond the timeout window. During reset assertion, the watchdog timer is held cleared and does not count, ensuring deterministic recovery behavior in the MAX6821YUK-T.

How does the manual reset (MR) input function on the MAX6821YUK-T?

The MR input on the MAX6821YUK-T is active-low with an internal 50kΩ pullup resistor to VCC. Pulling MR low forces immediate reset assertion, which remains active for the full reset timeout period (≥140ms) after MR returns high. If unused, MR can be left unconnected-the internal pullup holds it high. This eliminates external components and enables simple momentary switch interfaces, a key design feature of the MAX6821YUK-T for field-serviceable equipment.

What output type does the MAX6821YUK-T provide, and how does it interface with a microprocessor?

The MAX6821YUK-T provides a push-pull active-low RESET output. It drives low to ≤0.3V at 50µA (VCC ≥ 1.0V) and high to ≥0.8×VCC at 200µA (VCC ≥ 1.8V). This eliminates the need for an external pullup resistor and guarantees a defined logic state during both assertion and release, simplifying interface with µP reset pins-especially those lacking internal pullups or requiring strong drive strength, as specified in the MAX6821YUK-T datasheet.

Can the MAX6821YUK-T operate reliably at very low supply voltages?

Yes, the MAX6821YUK-T guarantees correct reset assertion down to VCC = +1.0V, and its operating voltage range is specified from +1.2V to +5.5V over –40°C to +125°C. This ensures deterministic behavior during deep brownout conditions where other supervisors may fail to assert reset. The internal circuitry remains functional and the RESET output maintains valid logic levels, a critical reliability feature confirmed in the MAX6821YUK-T's Absolute Maximum Ratings and Electrical Characteristics tables.