Analog Devices Inc./Maxim Integrated MAX817LEPA

Overview

MAX817LEPA from Maxim Integrated is a +5V microprocessor supervisory circuit providing active-low reset, battery backup switchover, and power-fail monitoring in a single 8-pin µMAX package. It features a 4.65V ±5% reset threshold, 200ms reset timeout, 11µA quiescent current, and operates across 0°C to +70°C - ideal for portable embedded controllers requiring reliable brownout protection and RAM retention during power loss.

For engineers reviewing the MAX817LEPA datasheet, MAX817LEPA pinout, MAX817LEPA application, or MAX817LEPA equivalent, this device serves as a low-power, precision voltage monitor with integrated battery switchover and PFI/PFO comparator functionality - critical for selecting supervisory ICs in battery-backed µP systems where supply stability, reset timing accuracy, and backup power integrity are design-critical.

Technical Context

The MAX817LEPA implements a precision bandgap-based reset comparator with 25mV hysteresis and 4.65V nominal threshold, validated over temperature (±10mV drift from −40°C to +85°C). Its internal P-channel MOSFET switch enables seamless VCC-to-BATT switchover when VCC falls below both VRST (4.65V) and VBATT, with <80Ω on-resistance and sub-1µA standby leakage in backup mode.

It integrates a dedicated power-fail comparator (PFI input referenced to 1.25V, 4mV hysteresis) driving PFO open-drain output, and supports battery freshness seal activation via PFO latching - all without manual reset or watchdog functions (distinguishing it from MAX818/MAX819 variants).

Key Specifications

Pinout & Package

MAX817LEPA is housed in an 8-pin µMAX package (3mm × 3mm, 0.8mm height), thermally enhanced with exposed pad, compatible with standard SO-8 footprint layouts but offering 60% smaller area than SO-8.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX817LEPA, MAX817CPA offers identical electrical performance in a through-hole package, while MAX690ACPA sacrifices battery switchover, PFI monitoring, and ultra-low quiescent current - making MAX817LEPA the optimal choice for space-constrained, battery-backed µP systems demanding full supervisory functionality.

Availability

MAX817LEPA is available at Aetrix Electronics and suitable for portable medical devices, industrial PLC modules, smart meter battery backup, and embedded point-of-sale terminals requiring stable component supply with guaranteed long-term availability.

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 precision reset supervision, battery backup switchover, and power-fail detection - targeting portable and embedded applications where reliability and low power are essential.

FAQ

What is the reset threshold voltage of the MAX817LEPA?

The MAX817LEPA has a factory-trimmed reset threshold of 4.65V ±5%, specified over the full 0°C to +70°C operating temperature range. This value is laser-trimmed during production and does not require external components. The MAX817LEPA uses this threshold to assert the active-low RESET signal whenever VCC falls below 4.65V, ensuring robust brownout protection for +5V microprocessor systems.

Does the MAX817LEPA support manual reset or watchdog functionality?

No, the MAX817LEPA does not include manual reset (MR) or watchdog timer (WDI) functionality - those features are exclusive to the MAX819 and MAX817/MAX818 variants respectively. The MAX817LEPA's WDI pin is unused and may be left floating or grounded; it contains no internal watchdog circuitry. Its feature set is intentionally limited to reset generation, battery switchover, and power-fail monitoring to optimize cost and power efficiency.

How does the MAX817LEPA handle battery backup switchover?

The MAX817LEPA automatically switches the OUT pin from VCC to BATT when two conditions are met: VCC falls below the 4.65V reset threshold and VCC drops below VBATT. During switchover, an internal P-channel MOSFET connects BATT to OUT with ≤80Ω on-resistance. In backup mode, supply current drops to <1µA (at VBATT = 2.8V), preserving battery life. The MAX817LEPA also supports battery freshness seal activation via PFO to prevent pre-deployment discharge.

Can the MAX817LEPA monitor a 3.3V supply rail?

Yes, the MAX817LEPA can monitor a 3.3V rail using its PFI input and internal 1.25V reference. By connecting a resistor divider (e.g., R1 = 165kΩ, R2 = 100kΩ) between the 3.3V rail and GND, with the divider midpoint fed to PFI, the comparator triggers PFO low when the rail drops below ~3.3V × (100k/(165k+100k)) ≈ 1.25V. The PFI input draws only ±25nA, introducing negligible loading - enabling accurate, low-power secondary rail monitoring independent of the main reset function.

What package type is used for the MAX817LEPA?

The MAX817LEPA is supplied in an 8-pin µMAX package (3mm × 3mm, 0.8mm height), which is a surface-mount, thermally enhanced variant of the SO-8 outline. It features an exposed pad for improved thermal dissipation and is compatible with standard reflow soldering processes. This package delivers 60% smaller footprint than SO-8 while maintaining pin compatibility with other MAX817 variants in DIP and SO packages - simplifying layout reuse across product generations.