Analog Devices Inc./Maxim Integrated MAX817LEPA+

Overview

MAX817LEPA+ from Maxim Integrated is a +5V microprocessor supervisory circuit with active-low reset, backup-battery switchover, and power-fail comparator functionality. It features a 4.65V ±5% reset threshold, 200ms reset timeout, 11µA quiescent supply current, and operates in 0°C to +70°C temperature range. It is used in portable battery-powered systems to ensure reliable µP startup, brownout recovery, and RAM backup during power failure.

For engineers reviewing the MAX817LEPA+ datasheet, MAX817LEPA+ pinout, MAX817LEPA+ application, or MAX817LEPA+ equivalent, this page delivers verified technical context, exact pin roles, real-world use scenarios, and validated alternative options for embedded power-monitoring designs requiring stable reset timing and battery-failover control.

Technical Context

The MAX817LEPA+ integrates a precision voltage monitor with 4.65V reset threshold and 25mV hysteresis, a 200ms internal reset timer, and a dedicated power-fail comparator (PFI/PFO) with 1.25V threshold. Its battery switchover circuit uses dual PMOS switches (5Ω VCC-to-OUT, 80Ω BATT-to-OUT) and supports VBATT > VCC operation with <1µA standby current when VCC is >0.2V below VBATT.

It implements a low-power supervisory architecture: RESET asserts on VCC drop below VRST or manual trigger (not applicable here-MAX817 lacks MR), PFO asserts on PFI <1.25V or VCC < VBATT, and OUT automatically routes to VCC or BATT based on voltage comparison and reset state-no external logic required.

Key Specifications

Pinout & Package

MAX817LEPA+ is housed in an 8-pin plastic DIP (PDIP) package with 0.3-inch width, standard for through-hole assembly and breadboard evaluation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX690ACPA+ and TPS3808G33DBVR, the MAX817LEPA+ uniquely combines +5V compatibility, integrated battery switchover, and independent power-fail detection - making it the sole option among these three for robust, self-contained 5V µP supervision with RAM backup capability.

Availability

MAX817LEPA+ is available at Aetrix Electronics and suitable for portable equipment, embedded controllers, and intelligent instruments requiring stable component supply across commercial temperature ranges and long-lifecycle production programs.

Supply support for MAX817LEPA+ 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, communications, and computing applications.

The MAX817L/M series was designed specifically for +5V microprocessor systems needing compact, low-power supervision with battery backup and power-fail warning - targeting portable and embedded applications where reliability and integration reduce BOM count.

FAQ

What is the reset threshold voltage of the MAX817LEPA+?

The MAX817LEPA+ has a factory-trimmed reset threshold of 4.65V ±5%, optimized for +5V systems. This value is guaranteed over temperature (0°C to +70°C) and ensures reset assertion before µP operational instability occurs. The threshold exhibits 25mV hysteresis to prevent oscillation during slow VCC ramps. This specification is confirmed in the Electrical Characteristics table of the official MAX817 datasheet Rev 3.

Does the MAX817LEPA+ support battery backup switching?

Yes, the MAX817LEPA+ supports automatic battery backup switching: when VCC falls below both the reset threshold (4.65V) and VBATT, the internal 80Ω PMOS switch connects BATT to OUT, powering attached CMOS RAM. The device draws <1µA from the battery in backup mode if VCC is >0.2V below VBATT. This function is fully integrated - no external MOSFETs or diodes are required for basic switchover.

Can the MAX817LEPA+ monitor a secondary power supply?

Yes, the MAX817LEPA+ includes a dedicated power-fail comparator with PFI input and PFO output. By connecting a resistor divider to PFI, users can monitor auxiliary voltages (e.g., 3.3V, 2.5V rails); PFO goes low when PFI falls below 1.25V. This path is electrically isolated from the reset generator, enabling independent low-voltage warnings without affecting µP reset behavior - a feature confirmed in the MAX817L/M selector guide and functional diagram.

What is the supply current of the MAX817LEPA+ in normal operation?

The MAX817LEPA+ draws 11µA typical supply current from VCC under normal operating conditions (VCC = 5V, TA = +25°C), as specified in the Electrical Characteristics table. This ultra-low quiescent current enables multi-year operation from primary lithium batteries in portable applications. Current increases slightly at temperature extremes but remains below 60µA across the full 0°C to +70°C range per Typical Operating Characteristics graphs.

Is the MAX817LEPA+ pin-compatible with other devices in the MAX817 family?

Yes, the MAX817LEPA+ shares identical 8-pin PDIP pinout with all MAX817 variants (e.g., MAX817CEPA+, MAX817MCPA+), as well as with MAX818 and MAX819 in the same package type. Pin functions - including OUT, VCC, GND, PFI, PFO, RESET, and BATT - are consistent across the family. However, WDI and MR pins are no-connection in MAX817, while functional in MAX818/MAX819; unused pins must be terminated per layout guidelines to avoid noise coupling.