Analog Devices Inc./Maxim Integrated MAX8868EUK28+

Overview

MAX8868EUK28+ from Maxim Integrated is a low-noise, low-dropout linear regulator with 2.8V preset output voltage, 150mA maximum output current, 30µVRMS output noise, and 165mV dropout at full load. It features an internal P-channel MOSFET pass transistor, 10nA logic-controlled shutdown, and auto-discharge functionality - designed for space-constrained, battery-powered portable electronics requiring stable, clean power.

For engineers reviewing the MAX8868EUK28+ datasheet, MAX8868EUK28+ pinout, MAX8868EUK28+ application, or MAX8868EUK28+ equivalent, key selection criteria include its 2.8V fixed output accuracy (±1.4%), thermal/short-circuit protection, reverse battery protection, and SOT23-5 thin-package compatibility in high-density handheld designs.

Technical Context

The MAX8868EUK28+ uses a 1.25V bandgap reference and error amplifier to regulate output via an internal P-channel MOSFET pass transistor (1.1Ω typical R_DS(ON)). Its feedback network is fully internal - no external resistors required - enabling factory-preset 2.8V output with ±1.4% accuracy over temperature and load.

It integrates BP-pin-based noise filtering (0.01µF capacitor creates 80Hz low-pass), 10nA shutdown mode with active output discharge, and thermal shutdown at +155°C with +15°C hysteresis. Reverse battery protection limits reverse current to 1mA when VIN or SHDN falls below ground.

Key Specifications

Pinout & Package

SOT23-5 thin package (JEDEC MO-178AA), 2.9mm × 1.6mm × 1.1mm body height - optimized for ultra-thin handheld PCBs with thermal performance enhanced by GND pin acting as heatsink.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-noise, fixed-output LDO applications.

Compared with MAX8867EUK28+, the MAX8868EUK28+ adds critical auto-discharge without sacrificing noise, dropout, or accuracy - making it uniquely suited for power-sequenced portable systems. Against MCP1700T-2802E/TT, it trades ultra-low quiescent current for superior noise performance, thermal robustness, and integrated protection - favoring RF/analog-sensitive designs over simple sensor nodes.

Availability

MAX8868EUK28+ is available at Aetrix Electronics and suitable for cellular handsets, PCMCIA cards, palmtop computers, and electronic planners requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for MAX8868EUK28+ 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 MAX8867/MAX8868 product line was engineered specifically for battery-powered portable electronics - prioritizing ultra-low noise, minimal dropout, and integrated protection in the smallest possible SOT23 footprint.

FAQ

What is the exact output voltage tolerance of the MAX8868EUK28+ over temperature and load?

The MAX8868EUK28+ delivers 2.8V output with ±1.4% accuracy across -40°C to +85°C ambient temperature and 0mA to 150mA load range. This specification is production-tested at +25°C and guaranteed over temperature via Statistical Quality Control correlation - ensuring consistent performance in handheld devices exposed to varying environmental conditions. The MAX8868EUK28+ achieves this without external components due to its factory-trimmed internal feedback divider.

Does the MAX8868EUK28+ require an external capacitor on the BP pin, and what happens if it's omitted?

Yes, the MAX8868EUK28+ requires a 0.01µF ceramic capacitor between BP and GND to achieve its specified 30µV_RMS output noise. Omitting this capacitor increases output noise to approximately 100µV_RMS, degrading performance in noise-sensitive applications like RF biasing or precision ADC references. The BP pin connects to an internal 200kΩ resistor forming an 80Hz low-pass filter - without the capacitor, reference noise passes unattenuated to the error amplifier.

How does the auto-discharge function of the MAX8868EUK28+ operate during shutdown?

When the SHDN pin is pulled low, the MAX8868EUK28+ activates an internal NMOS switch between OUT and GND, discharging the output capacitance to ground. This occurs independently of input voltage and continues until V_OUT reaches ~0.1V. The discharge resistance is specified at 300Ω (typical), enabling rapid discharge of typical 1–10µF output caps in under 1ms - eliminating floating outputs that could cause latch-up or false wake events in sequenced power systems.

Can the MAX8868EUK28+ be used with input voltages below 2.5V, such as a nearly depleted single-cell alkaline battery?

No - the MAX8868EUK28+ has a minimum input voltage rating of 2.5V per Absolute Maximum Ratings and Electrical Characteristics tables. Operation below 2.5V risks undefined behavior, including loss of regulation, increased dropout, or failure to maintain 2.8V output. With a 165mV dropout at 150mA, the lowest functional input is ~2.965V. For sub-2.5V operation, consider boost regulators or ultra-low-V_IN LDOs like the MAX1726, not the MAX8868EUK28+.

Is the MAX8868EUK28+ pin-compatible with the MAX8863/MAX8864 series, and what is the BP pin difference?

Yes, the MAX8868EUK28+ is pin-compatible with MAX8863/MAX8864 in SOT23-5 packages except for the BP pin: MAX8863/64 use BP for bias current setting, while MAX8868EUK28+ repurposes BP exclusively for noise reduction via 0.01µF capacitor. This means existing layouts using MAX8863/64 can accept MAX8868EUK28+ only if the BP net is reconfigured to host the noise-bypass cap - no other pin connections change, preserving IN, OUT, GND, and SHDN routing integrity.