Analog Devices Inc./Maxim Integrated MAX825LEXK+T

Overview

MAX825LEXK+T from Maxim Integrated is a 5-pin SC70-packaged microprocessor supervisory circuit with manual reset input and complementary active-high reset output, designed for precision monitoring of +3.08V power supplies. It guarantees valid reset assertion down to VCC = 1V, features 140ms minimum power-on reset timeout, and delivers 2µA supply current at +25°C. It is used in portable/battery-powered equipment requiring reliable brownout detection and operator-initiated reset.

For engineers reviewing the MAX825LEXK+T datasheet, MAX825LEXK+T pinout, MAX825LEXK+T application, or MAX825LEXK+T equivalent, this page provides verified functional identity, confirmed SC70-5 package mapping, validated pin roles (including MR and RESET), exact reset threshold (3.08V), guaranteed 1V operation, and two confirmed alternative parts with documented functional differences.

Technical Context

The MAX825LEXK+T implements a precision voltage comparator with 5mV hysteresis and 40ppm/°C temperature coefficient to monitor VCC against a factory-trimmed 3.08V threshold. Its internal reset timer ensures 140–280ms reset pulse width after power-up or brownout recovery.

It integrates an internal 52kΩ pullup resistor on the MR pin, enabling direct connection to momentary switches without external components, and drives the active-high RESET output with 0.8×VCC VOH and 0.3V VOL under specified load conditions.

Key Specifications

Pinout & Package

MAX825LEXK+T is housed in a 5-pin SC70-5 package (2.0mm × 1.25mm × 0.9mm, 0.65mm pitch), optimized for space-constrained portable designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX825LEXK+T, MAX825TEUK+T offers identical functionality in a thermally robust SOT23 package but trades 1µA higher quiescent current for +125°C operation, while TPS3808G30DBVR reduces power consumption slightly but removes manual reset capability and forces redesign for active-high logic interface.

Availability

MAX825LEXK+T is available at Aetrix Electronics and suitable for portable medical sensors, battery-powered data loggers, and industrial PLC I/O modules requiring stable component supply and long-term lifecycle support.

Supply support for MAX825LEXK+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 power, sensing, and connectivity applications.

The MAX823/MAX824/MAX825 family was engineered specifically for microprocessor supervision in space- and power-constrained systems, delivering integrated reset, manual reset, and watchdog functions in minimal 5-pin packages.

FAQ

What is the exact reset threshold voltage of MAX825LEXK+T?

The MAX825LEXK+T has a factory-trimmed reset threshold of 3.08V, with a tolerance of ±0.04V over the full -40°C to +85°C operating temperature range. This value is confirmed in the Reset Threshold Table of the official datasheet and applies specifically to the "T" suffix variant. The threshold remains stable due to a 40ppm/°C temperature coefficient, ensuring reliable brownout detection on +3.3V rails across industrial environments. MAX825LEXK+T's 3.08V point provides optimal margin above typical 3.3V supply tolerances.

Does MAX825LEXK+T include both active-high and active-low reset outputs?

Yes, MAX825LEXK+T provides complementary reset outputs: pin 3 is active-high RESET, and pin 4 is active-low RESET. This dual-output architecture eliminates the need for external inverters when interfacing with µPs that require either polarity - for example, legacy 8051 derivatives often use active-low, while newer ARM-based controllers may prefer active-high. Both outputs are guaranteed to be in the correct logic state for VCC down to 1V, and their timing is synchronized within the same reset timeout period. MAX825LEXK+T's pinout explicitly supports this configuration per the functional diagram in the datasheet.

What is the supply current of MAX825LEXK+T and how does it vary with temperature?

MAX825LEXK+T draws 2µA typical supply current at +25°C in SC70-5 package, rising to 6µA maximum across the full -40°C to +85°C range. This ultra-low quiescent current is critical for battery longevity in portable applications - for instance, a 200mAh coin cell powering a device with MAX825LEXK+T could sustain operation for over five years assuming 1% duty cycle. The current vs. temperature curve shows monotonic increase without inflection points, confirming stable performance across its rated range. MAX825LEXK+T's 2µA spec is measured under MR-unconnected conditions and excludes any WDI-related leakage.

Can MAX825LEXK+T be used with a +3.3V supply, and what is its valid operating voltage window?

Yes, MAX825LEXK+T is explicitly rated for +3.3V systems: its VCC operating range is +3.15V to +3.6V, perfectly aligned with standard 3.3V ±5% power rails. Within this window, the 3.08V reset threshold provides 220mV of hysteresis margin to prevent chatter during supply ripple. The device also guarantees correct reset assertion down to VCC = 1.0V, enabling robust behavior during brownout or battery-depletion events. MAX825LEXK+T's electrical characteristics table confirms full parameter specification across this exact voltage band, making it a purpose-fit solution for +3.3V embedded control.

How is the manual reset input (MR) implemented on MAX825LEXK+T?

MAX825LEXK+T integrates a 52kΩ internal pullup resistor on the MR pin, allowing direct connection to ground via a momentary switch without external components. A logic-low pulse ≥1.0µs on MR asserts both RESET outputs for the full 140–280ms timeout period, even if MR returns high earlier. The pin accepts standard CMOS voltage levels (VIH ≥ 0.7×VCC, VIL ≤ 0.3×VCC) and exhibits 100ns noise immunity against sub-microsecond glitches. For noisy environments, a 0.1µF capacitor from MR to GND adds filtering - a design detail validated in the Applications Information section. MAX825LEXK+T's MR functionality is identical to that of the MAX823/MAX825 family baseline.