Analog Devices Inc./Maxim Integrated MAX8887EZK28

Overview

MAX8887EZK28 from Maxim Integrated is a low-noise, 2.85V fixed-output, 300mA low-dropout linear regulator with 100mV dropout at 200mA, 42µVRMS output noise, and 55µA no-load supply current. It features thermal shutdown, short-circuit protection, and micropower shutdown (0.1µA), designed for power-sensitive portable systems including notebook computers and wireless handsets.

For engineers reviewing the MAX8887EZK28 datasheet, MAX8887EZK28 pinout, MAX8887EZK28 application, or MAX8887EZK28 equivalent, key selection criteria include guaranteed 300mA output under battery-sag conditions, ultra-low quiescent current independent of load, low-noise performance enabled by BP pin bypassing, and SOT23-5 package compatibility with space-constrained PCB layouts.

Technical Context

The MAX8887EZK28 uses an internal P-channel MOSFET pass transistor with ~0.5Ω R_DS(ON), enabling dropout voltage as low as 100mV at 200mA while maintaining 55µA ground current across full load range. Its error amplifier compares feedback from an internal 1.25V reference to regulate output without external resistors.

Noise reduction is implemented via dedicated BP (bypass) pin accepting a 0.01µF capacitor to filter reference noise, yielding 42µVRMS output noise (10Hz–100kHz). The device lacks POK functionality-exclusive to MAX8888 variants-and operates only in fixed 2.85V output mode per its EZK28 suffix.

Key Specifications

Pinout & Package

MAX8887EZK28 is housed in a thin 5-pin SOT23 package (1mm height), optimized for high-density portable PCBs. Pin assignments are validated per Maxim's official pin configuration diagram for MAX8887.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS78228DRVT and NCP1117ST28T3G, the MAX8887EZK28 uniquely balances ultra-low quiescent current (55µA), user-tunable noise performance via BP pin, and industry-leading 100mV dropout-making it optimal for space- and battery-limited portable designs demanding both precision and longevity.

Availability

MAX8887EZK28 is available at Aetrix Electronics and suitable for notebook computers, wireless handsets, and digital cameras requiring stable component supply with guaranteed long-term availability and consistent parametric performance.

Supply support for MAX8887EZK28 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 demanding applications.

The MAX8887/MAX8888 family was designed specifically for battery-powered portable electronics, emphasizing ultra-low quiescent current, low-noise regulation, and minimal board footprint in SOT23 packaging.

FAQ

What is the exact output voltage tolerance of the MAX8887EZK28 over temperature and load?

The MAX8887EZK28 guarantees ±2% output voltage accuracy over load current (100µA to 300mA) and temperature (-40°C to +85°C), with tighter ±1.2% typical accuracy at +25°C and 100mA load. This specification ensures reliable operation of 2.85V I/O interfaces in portable devices across real-world environmental and loading conditions. The MAX8887EZK28 achieves this via laser-trimmed internal feedback resistors and a stable 1.25V bandgap reference.

Does the MAX8887EZK28 support adjustable output voltage?

No, the MAX8887EZK28 provides only a factory-set fixed 2.85V output. Its EZK28 suffix explicitly denotes this preset value, and the device lacks external feedback pins or resistor-divider connections for adjustment. All regulation is handled internally using trimmed resistors tied to a 1.25V reference. For adjustable versions, engineers must select other families such as MAX8860 or MAX8863 - the MAX8887EZK28 is strictly a fixed-output LDO.

How does the BP pin on the MAX8887EZK28 improve noise performance?

The BP (bypass) pin on the MAX8887EZK28 connects directly to the internal voltage reference node, allowing a 0.01µF ceramic capacitor to form a low-pass filter that attenuates reference noise before it modulates the error amplifier. This design reduces total output noise to 42µVRMS (10Hz–100kHz), a key differentiator versus standard LDOs. Without the BP capacitor, noise increases significantly - the MAX8887EZK28's BP pin is mandatory to achieve its specified low-noise performance.

Can the MAX8887EZK28 be used with ceramic output capacitors below 2.2µF?

No - the MAX8887EZK28 requires a minimum 2.2µF ceramic output capacitor with ESR ≤ 0.1Ω for guaranteed stability, as confirmed in Maxim's application notes and electrical characteristics table. Using smaller values (e.g., 1µF) risks oscillation under load transients, especially near dropout. The 2.2µF value is tightly coupled to internal compensation; reducing it compromises phase margin and may cause sustained ringing or thermal shutdown during dynamic loads. Always place COUT within 3mm of the MAX8887EZK28 OUT and GND pins.

Is the MAX8887EZK28 pin-compatible with the MAX8888 series?

No - although both share the SOT23-5 package and identical IN/GND/SHDN/OUT pin positions, the MAX8887EZK28 uses Pin 4 as BP (bypass), whereas the MAX8888 uses Pin 4 as POK (power-ok). Swapping them causes functional failure: connecting a MAX8887EZK28's BP pin to a POK pullup network disrupts noise filtering, and driving POK logic into a MAX8887EZK28's BP node can damage the reference circuit. They are functionally distinct parts with incompatible pin functions despite mechanical similarity.