Analog Devices Inc./Maxim Integrated MAX8878EUK28

Overview

MAX8878EUK28 from Maxim Integrated is a low-noise, low-dropout linear regulator with 2.8V preset output, 150mA maximum output current, 165mV dropout at full load, 30µVRMS output noise, and 100µA operating supply current. It features auto-discharge during shutdown and reverse battery protection, designed for space-constrained portable electronics requiring stable, clean power from single-cell Li-ion or alkaline sources.

For engineers reviewing the MAX8878EUK28 datasheet, MAX8878EUK28 pinout, MAX8878EUK28 application, or MAX8878EUK28 equivalent, key selection criteria include its SOT23-5 package compatibility with '2982 footprints, guaranteed ±1.4% output voltage accuracy over temperature, thermal and short-circuit protection, and BP-capacitor–enabled noise filtering for RF-sensitive analog circuits.

Technical Context

The MAX8878EUK28 uses an internal P-channel MOSFET pass transistor (1.1Ω typical R_DS(ON)) to achieve low dropout and eliminate base-drive current loss. Its error amplifier compares a 1.25V bandgap reference against feedback from an internal resistor divider tied to the OUT pin.

It integrates logic-controlled shutdown (10nA I_SHDN), thermal shutdown at +155°C with 15°C hysteresis, current limiting (160–390mA), and reverse-battery protection that limits reverse current to 1mA. The MAX8878 variant uniquely adds active output discharge via a 300Ω internal resistance when SHDN is asserted.

Key Specifications

Pinout & Package

SOT23-5 regular package (JEDEC MO-178AA); 5-pin surface-mount with exposed pad not present; footprint compatible with industry-standard '2982 regulators; thermal performance optimized via GND pin soldered to large copper area.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX8878EUK28, MAX8877EUK28 omits auto-discharge and has higher shutdown current, while XC6206P282MR trades noise and protection features for higher output current and different pin assignment-making MAX8878EUK28 optimal for compact, safety-critical, noise-sensitive portable designs requiring guaranteed discharge behavior.

Availability

MAX8878EUK28 is available at Aetrix Electronics and suitable for cellular handsets, PCMCIA cards, palmtop computers, and electronic planners requiring stable component supply, long-lifecycle support, and guaranteed parametric compliance across industrial temperature range.

Supply support for MAX8878EUK28 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 MAX8877/MAX8878 product line delivers ultra-low-noise, low-quiescent-current LDOs optimized for battery-powered portable devices where runtime, signal integrity, and physical size are critical constraints.

FAQ

What is the output voltage tolerance of the MAX8878EUK28 over temperature and load?

The MAX8878EUK28 guarantees ±1.4% output voltage accuracy across the full -40°C to +85°C operating temperature range and for load currents from 0.1mA to 120mA. At +25°C and 0.1mA load, the tolerance tightens to ±1.4% (not ±1.0%), and the device maintains this specification even under dropout conditions due to its P-channel MOSFET architecture. This accuracy ensures reliable operation of precision analog circuitry without external trimming.

Does the MAX8878EUK28 require an external BP capacitor, and what happens if it is omitted?

Yes, the MAX8878EUK28 requires a 0.01µF ceramic capacitor between BP and GND to achieve its specified 30µVRMS output noise. Omitting this capacitor increases output noise to approximately 100µVRMS and degrades PSRR above 1kHz. The BP pin connects internally to a 200kΩ resistor forming an 80Hz low-pass filter; without the capacitor, reference noise couples directly into the error amplifier, raising broadband noise and potentially affecting sensitive RF or audio stages powered by MAX8878EUK28.

How does the auto-discharge function of the MAX8878EUK28 operate, and what is its resistance value?

The MAX8878EUK28 activates its auto-discharge function when the SHDN pin is driven low: an internal 300Ω switch connects the OUT pin to GND, actively discharging any stored charge in the output capacitor. This path sinks current until V_OUT reaches ~0.1V, typically within tens to hundreds of microseconds depending on C_OUT value. Unlike passive bleed resistors, this controlled discharge prevents back-powering of upstream circuitry and eliminates residual voltage that could interfere with system reset sequencing or cause latch-up in downstream logic.

Can the MAX8878EUK28 be used with input voltages below 2.5V?

No, the MAX8878EUK28 has a minimum input voltage rating of 2.5V per Absolute Maximum Ratings and Electrical Characteristics tables. Operation below 2.5V risks improper biasing of internal circuitry, loss of regulation, and undefined behavior-including failure to maintain output accuracy or activate protection features. For sub-2.5V inputs, alternative regulators such as the MAX8526 (1.6V min VIN) or TPS7A05 (1.4V min VIN) should be evaluated, as MAX8878EUK28 is not characterized or guaranteed for operation in that range.

What thermal derating applies to the MAX8878EUK28 in SOT23-5 regular package?

In the SOT23-5 regular package, the MAX8878EUK28 has a continuous power dissipation limit of 571mW at +70°C ambient, with derating at 7.1mW/°C above that temperature. This corresponds to a junction-to-board thermal resistance (θ_JB) of 140°C/W. To sustain full 150mA output at elevated ambient temperatures, the GND pin must be soldered to ≥100mm² of 1oz copper; insufficient copper area will cause premature thermal shutdown, especially when VIN exceeds 4.5V and dropout power loss rises.