Analog Devices Inc./Maxim Integrated MAX8868EZK25-T

Overview

MAX8868EZK25-T from Maxim Integrated is a low-noise, low-dropout linear regulator with 2.5V preset output, 150mA output current capability, 30µVRMS output noise, and 165mV dropout at full load. It features auto-discharge during shutdown, reverse battery protection, and operates from 2.5V to 6.5V input - ideal for space-constrained battery-powered handheld instruments and PCMCIA cards.

For engineers reviewing the MAX8868EZK25-T datasheet, MAX8868EZK25-T pinout, MAX8868EZK25-T application, or MAX8868EZK25-T equivalent, key selection criteria include its thin SOT23-5 package, 10nA shutdown current, ±1.4% output accuracy, thermal/short-circuit protection, and BP-pin noise-filtering architecture.

Technical Context

The MAX8868EZK25-T uses an internal P-channel MOSFET pass transistor (1.1Ω typical R_DS(ON)) to achieve low quiescent current (100µA across load and dropout conditions) and eliminate base-drive losses inherent in PNP-based regulators. Its error amplifier compares a 1.25V bandgap reference against feedback from an internal resistor divider tied to the OUT pin.

Unlike the MAX8867, the MAX8868EZK25-T integrates auto-discharge circuitry activated by the SHDN pin, actively pulling the output to GND during shutdown. The BP pin connects to an internal 200kΩ resistor forming an 80Hz low-pass filter with an external 0.01µF capacitor, directly reducing output voltage noise.

Key Specifications

Pinout & Package

MAX8868EZK25-T is housed in a thin 5-pin SOT23 package (JEDEC MO-178AA), optimized for PCB area and thermal performance via GND pin heatsinking. The GND pin serves dual electrical and thermal roles and must be soldered to a large copper pour.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX8867EZK25-T, the MAX8868EZK25-T adds critical auto-discharge without sacrificing noise, dropout, or quiescent current - making it uniquely suited for systems requiring clean power-state transitions. Versus MCP1700T-2502E/MB, it delivers superior noise performance, integrated protection, and a dedicated BP filter node unavailable in 3-pin alternatives.

Availability

MAX8868EZK25-T is available at Aetrix Electronics and suitable for hand-held instruments, PCMCIA cards, palmtop computers, and electronic planners requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.

Supply support for MAX8868EZK25-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 MAX8867/MAX8868 product line was designed specifically for ultra-low-noise, low-quiescent-current regulation in space-constrained, battery-powered portable electronics - emphasizing dropout efficiency, output accuracy, and integrated protection.

FAQ

What is the exact output voltage tolerance of the MAX8868EZK25-T?

The MAX8868EZK25-T has a factory-preset output voltage of 2.5V with a guaranteed accuracy of ±1.4% over the full operating temperature range (-40°C to +85°C). This specification is 100% production tested at +25°C and correlation-validated across temperature using Statistical Quality Control methods - ensuring consistent performance in battery-powered handheld instruments and PCMCIA cards where voltage drift affects ADC linearity and logic compatibility.

Does the MAX8868EZK25-T require an external capacitor on the BP pin, and why?

Yes, the MAX8868EZK25-T requires a 0.01µF ceramic capacitor between the BP pin and GND. This capacitor forms an 80Hz low-pass filter with an internal 200kΩ resistor to suppress reference voltage noise before it reaches the error amplifier. Without it, output noise increases significantly - measured data shows 30µV_RMS with CBP = 0.01µF versus >50µV_RMS with no capacitor. The MAX8868EZK25-T's BP architecture is a key differentiator for noise-sensitive applications like precision sensor interfaces.

How does the auto-discharge feature of the MAX8868EZK25-T operate during shutdown?

When the SHDN pin is pulled low, the MAX8868EZK25-T disables regulation and activates an internal discharge FET that actively pulls the OUT pin to GND. This occurs within microseconds and holds V_OUT ≤ 50mV until SHDN is released. Unlike passive RC discharge, this feature ensures rapid, deterministic output collapse - critical for preventing back-powering of upstream circuitry or false wake events in palmtop computers and electronic planners using the MAX8868EZK25-T.

What thermal considerations apply to the MAX8868EZK25-T in its thin SOT23 package?

The MAX8868EZK25-T in thin SOT23 has a junction-to-board thermal resistance (θ_JB) of 110°C/W. To maintain T_J ≤ 150°C at 150mA load with 6.5V input (worst-case power dissipation ≈ 600mW), the PCB must provide adequate copper area on the GND pad - typically ≥ 100mm² of 1oz copper connected via multiple vias to inner ground planes. The GND pin is both electrical return and primary thermal path; insufficient copper will trigger thermal shutdown at ambient temperatures as low as +40°C.

Can the MAX8868EZK25-T be used with input voltages below 2.5V?

No, the MAX8868EZK25-T 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 potential failure to enter or exit shutdown correctly. For sub-2.5V inputs, alternative regulators such as the MAX1726 (1.8V min) or MAX8881 (1.6V min) must be selected; the MAX8868EZK25-T is strictly specified for 2.5V–6.5V operation.