Analog Devices Inc./Maxim Integrated MAX824REUK-T

Overview

MAX824REUK-T from Maxim Integrated is a 5-pin SOT23 microprocessor supervisory circuit with active-low and active-high reset outputs, watchdog timer (1.6s timeout), and precision +2.63V reset threshold. It operates from -40°C to +125°C, draws 3–8µA supply current, and guarantees RESET validity down to VCC = 1V. It is used in automotive systems and critical µP monitoring where transient immunity and dual-reset polarity are required.

For engineers reviewing the MAX824REUK-T datasheet, MAX824REUK-T pinout, MAX824REUK-T application, or MAX824REUK-T equivalent, key selection criteria include its dual-reset output polarity, 2.63V threshold accuracy over temperature, watchdog timeout tolerance, SOT23-5 package compatibility, and operation at extended industrial temperature range.

Technical Context

The MAX824REUK-T integrates a precision voltage comparator with 40ppm/°C temperature coefficient, a 140ms minimum power-on reset timeout, and a watchdog timer that clears on WDI edge transitions. Its dual-reset outputs (RESET and RESET) provide complementary logic states for interfacing with bidirectional µP reset pins or level-sensitive peripherals.

It features internal MR pullup (52kΩ), 100ns MR noise immunity, and guaranteed reset assertion during VCC brownout down to 1V. The device ignores fast VCC transients via hysteresis (5mV for R-suffix) and supports CMOS-level manual reset input without external components.

Key Specifications

Pinout & Package

MAX824REUK-T is housed in a 5-pin SOT23-5 package (JEDEC MO-178AA), 2.9mm × 1.6mm × 1.1mm, lead-free compatible, tape-and-reel packaged (2500 pcs/reel).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX824REUK-T, MAX824SEUK-T offers identical functionality at a different threshold for alternate supply rails, while TPS3808G33DBVR reduces feature set and current consumption but sacrifices watchdog capability and reset polarity flexibility - making it unsuitable for safety-critical or dual-interface designs.

Availability

MAX824REUK-T is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLC controllers, and battery-powered data loggers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX824REUK-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, automotive, and computing applications.

The MAX823/MAX824/MAX825 family was engineered specifically for high-reliability µP supervision in harsh environments, emphasizing transient immunity, dual-reset flexibility, and extended temperature operation - not general-purpose voltage monitoring.

FAQ

What is the exact reset threshold voltage of the MAX824REUK-T and how tightly is it specified?

The MAX824REUK-T has a nominal reset threshold of 2.63V, with a tolerance of ±1.5% over the full operating temperature range (-40°C to +125°C). This specification is guaranteed by design and production-tested per Maxim's datasheet, ensuring accurate monitoring of +2.7V supply rails without external calibration. The device also features 5mV hysteresis and 40ppm/°C temperature coefficient, maintaining stability across thermal stress.

Does the MAX824REUK-T support both active-low and active-high reset outputs simultaneously?

Yes, the MAX824REUK-T provides simultaneous active-low RESET (pin 1) and active-high RESET (pin 3) outputs. Both signals are asserted/deasserted in strict complementarity - when RESET is low, RESET is high, and vice versa - enabling direct interface to µPs or peripherals requiring either polarity without external logic. This dual-output architecture is intrinsic to the MAX824 variant and confirmed in the Pin Description and Functional Diagram sections of the datasheet.

What is the watchdog timeout period of the MAX824REUK-T and how is it triggered?

The MAX824REUK-T watchdog timeout period is 1.6 seconds nominal, with a guaranteed range of 1.12s to 2.40s over temperature. It is triggered when the WDI input (pin 4) remains static - neither rising nor falling - for longer than this interval. The timer clears on any WDI edge transition, including pulses as short as 50ns, and is disabled if WDI is left unconnected or driven by a three-stated buffer.

Can the MAX824REUK-T operate reliably at VCC = 1V, and what happens to the reset outputs at that voltage?

Yes, the MAX824REUK-T guarantees correct reset output state (RESET low, RESET high) down to VCC = 1V, as explicitly stated in the General Description and Electrical Characteristics tables. At this voltage, the internal comparator remains functional, and RESET remains asserted until VCC rises above 2.63V and the 140ms timeout expires. This ensures safe µP hold-in-reset during deep brownout conditions common in automotive and battery-depleted scenarios.

Is the MAX824REUK-T pin-compatible with other devices in the MAX823/MAX824/MAX825 family?

Yes, the MAX824REUK-T is fully pin-compatible with all SOT23-5 variants in the MAX823/MAX824/MAX825 family, including MAX824LEUK-T, MAX824MEUK-T, and MAX825REUK-T. All share identical pinout (RESET, GND, RESET, WDI, VCC), package dimensions, and footprint. Functionality differs only in enabled features (e.g., MR input absent in MAX824) and reset threshold - confirming mechanical and layout interchangeability per the Selector Guide and Pin Configurations diagrams.