Analog Devices Inc./Maxim Integrated MAX8885EUK25+T

Overview

MAX8885EUK25+T from Maxim Integrated is a 2.5V fixed-output, 150mA low-dropout linear regulator with P-channel MOSFET pass element, 85µA no-load supply current, 110mV dropout at 100mA, and active-low open-drain Power-OK (POK) output. It operates from +2.5V to +6.5V input and is optimized for portable battery-powered systems using low-cost high-ESR tantalum capacitors - e.g., PCS phones and palmtop computers.

For engineers reviewing the MAX8885EUK25+T datasheet, MAX8885EUK25+T pinout, MAX8885EUK25+T application, or MAX8885EUK25+T equivalent, key selection considerations include its 2.5V ±1% output accuracy, reverse-battery protection, thermal shutdown with 20°C hysteresis, 1µA max shutdown current, and SOT23-5 package compatibility with space-constrained PCB layouts.

Technical Context

The MAX8885EUK25+T implements a 1.25V bandgap reference and error amplifier driving an internal P-channel MOSFET pass transistor (R_DS(ON) ≈ 1.1Ω), enabling ultra-low quiescent current independent of load. Its feedback network is fully internal, fixing V_OUT at 2.5V with ±1% accuracy over temperature and line/load conditions.

Power-OK monitoring uses an open-drain comparator referenced to 95% of nominal output; POK asserts low when V_OUT drops below 2.375V (2.5V × 0.95). Thermal protection activates at +170°C with +20°C hysteresis, and reverse-battery protection limits reverse current to ≤1mA when VIN or SHDN falls below GND.

Key Specifications

Pinout & Package

MAX8885EUK25+T is housed in a 5-pin SOT23-5 package (JEDEC MO-178AA), with GND serving dual electrical and thermal functions. The package requires soldering to a large copper pad or ground plane for effective heat dissipation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with MAX8875EUK25+T and MIC5206-2.5YM5-TR, the MAX8885EUK25+T uniquely combines POK supervision, reverse-battery protection, and high-ESR capacitor compatibility - making it the only choice for cost-sensitive, battery-powered devices requiring both reliability and long shelf life.

Availability

MAX8885EUK25+T is available at Aetrix Electronics and suitable for PCS phones, palmtop computers, electronic planners, and PCMCIA cards requiring stable component supply, consistent parametric performance, and long-term production continuity.

Supply support for MAX8885EUK25+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) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, communications, and consumer applications.

The MAX8885 series was designed specifically for portable battery-powered equipment needing ultra-low IQ, robust fault protection, and compatibility with inexpensive tantalum output capacitors - targeting cost-sensitive, space-constrained handheld devices.

FAQ

What is the output voltage tolerance of the MAX8885EUK25+T over temperature and load?

The MAX8885EUK25+T guarantees ±1% output voltage accuracy over the full operating temperature range (-40°C to +85°C) and across load currents from 100µA to 150mA. This specification is verified by production testing at +25°C and correlated over temperature using Statistical Quality Control methods - ensuring consistent 2.5V regulation for precision analog and digital circuitry in the MAX8885EUK25+T.

Can the MAX8885EUK25+T be used with ceramic output capacitors?

No - the MAX8885EUK25+T is explicitly designed for high-ESR tantalum capacitors (≥0.5Ω) and becomes unstable with low-ESR ceramic capacitors. Using ceramic output caps may cause oscillation or poor transient response. For ceramic-capable alternatives, refer to the pin-compatible MAX8875EUK25+T, which specifies COUT ≥1µF with ESR < 0.1Ω - the MAX8885EUK25+T must use 4.7µF tantalum with appropriate ESR.

How does the Power-OK (POK) output function in the MAX8885EUK25+T?

The POK pin on the MAX8885EUK25+T is an open-drain N-channel MOSFET that pulls low when V_OUT falls below 95% of nominal (2.375V), indicating undervoltage or regulation loss. It remains inactive during shutdown. A 100kΩ pull-up resistor to OUT generates a logic-high signal during normal operation; this signal can drive a µC reset input directly - the POK behavior is integral to the MAX8885EUK25+T's system-level supervision capability.

What thermal protection features does the MAX8885EUK25+T include?

The MAX8885EUK25+T incorporates thermal shutdown that disables the pass transistor when junction temperature exceeds +170°C, with automatic recovery once temperature falls to +150°C (20°C hysteresis). This prevents permanent damage during sustained overload or poor PCB thermal design. The GND pin serves as a thermal path - proper connection to a large copper area is essential for the MAX8885EUK25+T to sustain rated current without triggering thermal cycling.

Does the MAX8885EUK25+T provide reverse-battery protection, and how does it work?

Yes - the MAX8885EUK25+T includes reverse-battery protection that limits reverse current to ≤1mA when VIN or SHDN falls below GND. Internal circuitry detects polarity reversal and disconnects parasitic paths, preventing damage during incorrect battery installation. This feature is unique to the MAX8885EUK25+T among comparable 150mA LDOs and is critical for field-replaceable battery compartments in consumer handhelds.