Analog Devices Inc./Maxim Integrated MAX814LESA+T

Overview

MAX814LESA+T from Maxim Integrated is a high-accuracy, low-power microprocessor supervisory circuit providing power-on reset, manual reset, and early power-fail warning functions for +5V systems. It features ±1% worst-case reset threshold accuracy (4.70V), 200ms reset pulse width, active-low RESET output, 75µA max supply current, and guaranteed RESET validity down to VCC = 1V. It is used in medical equipment and portable battery-powered controllers requiring reliable brownout detection.

For engineers reviewing the MAX814LESA+T datasheet, MAX814LESA+T pinout, MAX814LESA+T application, or MAX814LESA+T equivalent, key selection criteria include reset threshold tolerance (±1%), low quiescent current (75µA), VCC-operating range (4.75V–5.5V), manual reset input compatibility, and power-fail comparator reference (2.50V).

Technical Context

The MAX814LESA+T implements a precision voltage-monitoring architecture with independent reset and power-fail comparators. Its reset comparator uses a trimmed bandgap reference to achieve ±1% threshold accuracy over temperature and supply variation, while the power-fail comparator operates at a fixed 2.50V reference with ±2% accuracy.

It integrates a low-line detector (60mV above reset threshold) and internal 150µA MR pull-up, enabling direct switch-to-ground manual reset without external components. The device asserts RESET low on power-up until VCC exceeds 4.70V and holds it for ≥200ms after threshold crossing.

Key Specifications

Pinout & Package

MAX814LESA+T is housed in an 8-pin SO (Small Outline) package with gull-wing leads, RoHS-compliant and lead-free (+T suffix). Pin 1 is MR (Manual Reset Input), Pin 2 is VCC, Pin 3 is GND, Pin 4 is PFI (Power-Fail Input), Pin 5 is PFO (Power-Fail Output), Pin 6 is LOW LINE (Low-Line Detector Output), Pin 7 is RESET (active-low reset output), and Pin 8 is RESET (active-high reset output).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX814LESA+T, MAX814LESA+ offers identical supervision but lacks RoHS compliance, while TPS3808G33DBVR targets lower-voltage systems with different timing and feature sets-neither is pin-compatible nor functionally interchangeable without board redesign.

Availability

MAX814LESA+T is available at Aetrix Electronics and suitable for medical equipment, portable/battery-powered equipment, and industrial controllers requiring stable component supply across extended temperature ranges (-40°C to +85°C) and long-term production cycles.

Supply support for MAX814LESA+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 MAX814/MAX815/MAX816 family was engineered specifically for high-reliability microprocessor supervision in systems where reset accuracy, low power, and multi-rail monitoring are critical-especially in portable and safety-critical equipment.

FAQ

What is the exact reset threshold voltage of the MAX814LESA+T?

The MAX814LESA+T has a factory-trimmed reset threshold of 4.70V with ±1% worst-case accuracy over temperature and supply variation. This value is confirmed in the Electrical Characteristics table for "MAX814L" parts under +5V conditions, where VRT (Reset Threshold) is specified as 4.75V (min), 4.83V (typ), and 4.93V (max) at VCC rising, corresponding to a nominal 4.70V ±1% trip point. The 'L' suffix explicitly denotes this 4.7V threshold variant.

Does the MAX814LESA+T support manual reset functionality?

Yes, the MAX814LESA+T supports manual reset via Pin 1 (MR). When MR is pulled below 1.10V, RESET is asserted low. The internal 150µA pull-up allows direct connection to a momentary switch to ground without external components. After MR returns high, RESET remains low for a guaranteed minimum of 200ms, ensuring robust µP reset initiation regardless of switch bounce or timing jitter.

What is the purpose of the LOW LINE output on the MAX814LESA+T?

The LOW LINE output (Pin 6) is a dedicated low-line detector that asserts low when VCC falls to approximately 60mV above the 4.70V reset threshold (i.e., ~4.76V). It provides an early warning signal-typically routed to a µP NMI input-allowing firmware to initiate data save or graceful shutdown before full reset occurs. This feature is unique to the MAX814 and is absent in MAX815/MAX816 variants.

Can the MAX814LESA+T monitor voltages other than VCC?

Yes, the MAX814LESA+T can monitor auxiliary voltages using the PFI (Pin 4) and PFO (Pin 5) pins. By connecting a resistive divider from the target rail (e.g., +12V) to PFI, the internal 2.50V comparator detects when the divided voltage falls below threshold. PFO then asserts low, enabling µP interrupt-driven response. This capability is documented in Figures 1 and 11 of the datasheet and supports both positive and negative rail monitoring with appropriate external circuitry.

What is the maximum supply voltage and operating temperature range for the MAX814LESA+T?

The MAX814LESA+T operates from VCC = 4.75V to 5.5V and is rated for the extended temperature range of -40°C to +85°C. Absolute maximum VCC is +6.0V, but functional operation is guaranteed only within the 4.75V–5.5V range. The 'E' grade designation in the ordering information (e.g., MAX814LESA+T) confirms the -40°C to +85°C specification, making it suitable for industrial and automotive-adjacent applications.