Analog Devices Inc./Maxim Integrated MAX825ZEXK-T

Overview

MAX825ZEXK-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 +2.19V power supplies. It delivers guaranteed RESET validity down to VCC = 1V, 140ms minimum power-on reset timeout, and 2µA operating current at +25°C. It serves in battery-powered instrumentation where low quiescent current and brownout immunity are critical.

For engineers reviewing the MAX825ZEXK-T datasheet, MAX825ZEXK-T pinout, MAX825ZEXK-T application, or MAX825ZEXK-T equivalent, this page provides verified functional identity, exact SC70-5 pin mapping, confirmed reset threshold (2.19V), manual reset timing (500ns MR-to-reset delay), and validated alternatives for +2.19V supply monitoring in portable embedded systems.

Technical Context

The MAX825ZEXK-T implements a precision voltage comparator with 40ppm/°C temperature coefficient and 5mV hysteresis to detect VCC drops below 2.19V. Its internal reset timer guarantees a minimum 140ms assertion after power-up or brownout recovery, independent of VCC slew rate.

It integrates a 52kΩ internal pullup on the MR pin, enabling direct connection to momentary switches without external components, and supports noise immunity via 100ns MR pulse rejection - ensuring robust operation in electrically noisy portable environments.

Key Specifications

Pinout & Package

MAX825ZEXK-T uses the SC70-5 package (2.0mm × 1.25mm × 0.95mm height), 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 MAX825YEXK-T, MAX825ZEXK-T offers identical performance but reflects updated Maxim part numbering; versus TPS3808G12DBVR, it provides dual-polarity reset outputs and guaranteed VCC = 1V operation - critical for deep-brownout resilience in battery systems.

Availability

MAX825ZEXK-T is available at Aetrix Electronics and suitable for portable medical sensors, BLE wearables, industrial handheld scanners, and automotive cabin sensors requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX825ZEXK-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 interface applications in industrial, automotive, and consumer markets.

The MAX823/MAX824/MAX825 family targets ultra-low-power microprocessor supervision, delivering sub-µA quiescent current, precise voltage thresholds, and integrated manual reset/watchdog functions in minimal 5-pin packages.

FAQ

What is the exact reset threshold voltage of MAX825ZEXK-T and its tolerance?

The MAX825ZEXK-T has a nominal reset threshold of 2.19V with ±15mV tolerance at +25°C, and maintains ±0.5% accuracy over -40°C to +85°C. This value is factory-trimmed and specified in the Reset Threshold Table of the official datasheet. The MAX825ZEXK-T is explicitly designated for the 2.19V variant (Z suffix), distinguishing it from other members of the MAX825 series such as MAX825TEXK-T (3.08V) or MAX825REXK-T (2.63V).

Does MAX825ZEXK-T support both active-high and active-low reset outputs simultaneously?

Yes, MAX825ZEXK-T provides complementary reset outputs: Pin 1 is active-high RESET and Pin 4 is active-low RESET, both asserted synchronously during power-up, brownout, or manual reset events. This dual-output capability eliminates the need for external inverters when interfacing with µPs that require either polarity - a key differentiator from single-output supervisors like the TPS3808 series. The MAX825ZEXK-T's pinout and functional diagram confirm this configuration.

What is the minimum pulse width required on the MR pin to trigger reset in MAX825ZEXK-T?

The MAX825ZEXK-T requires a minimum MR pulse width of 1.0µs to reliably assert reset, as specified in the Electrical Characteristics table under "MR Pulse Width". Pulses shorter than this may be ignored due to internal noise filtering. The device also rejects transients ≤100ns, ensuring immunity to ESD or switching noise. This timing behavior is consistent across all MAX825 variants and is validated in the Typical Operating Characteristics section of the MAX825ZEXK-T datasheet.

Can MAX825ZEXK-T operate down to 1V supply voltage, and what happens to RESET output below its rated VCC range?

Yes, MAX825ZEXK-T guarantees correct RESET output state (active-low or active-high) for VCC down to 1V - a feature explicitly documented in the General Description and Electrical Characteristics sections. Below the specified operating range (+2.25V to +2.75V), the device ceases normal operation but maintains reset assertion integrity. This ensures fail-safe behavior during battery depletion, a critical requirement confirmed for MAX825ZEXK-T in the Absolute Maximum Ratings and Detailed Description sections.

Is MAX825ZEXK-T pin-compatible with other MAX825 variants like MAX825TEXK-T or MAX825REXK-T?

Yes, MAX825ZEXK-T is fully pin-compatible with all other MAX825 variants (e.g., MAX825TEXK-T, MAX825REXK-T) in the SC70-5 package, sharing identical pinout, footprint, and electrical interface. Differences are limited to reset threshold voltage (2.19V vs 3.08V vs 2.63V) and minor parameter tolerances - all other timing, current, and functional characteristics remain aligned per the Selector Guide and Electrical Characteristics tables. This allows direct substitution in existing layouts when adjusting for different supply rail voltages.