Analog Devices Inc./Maxim Integrated MAX8878EUK33+T

Overview

MAX8878EUK33+T from Maxim Integrated is a low-noise, low-dropout linear regulator with fixed 3.3V output, 150mA maximum load capability, 165mV dropout at full load, 30µVRMS output noise, and 100µA operating supply current - designed for battery-powered portable electronics requiring stable, clean voltage rails.

For engineers reviewing the MAX8878EUK33+T datasheet, MAX8878EUK33+T pinout, MAX8878EUK33+T application, or MAX8878EUK33+T equivalent, key selection criteria include its auto-discharge function, SOT23-5 regular package compatibility with '2982 footprint, ±1.4% output accuracy over temperature, and reverse-battery protection for single-cell Li-ion or alkaline systems.

Technical Context

The MAX8878EUK33+T 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 thermal shutdown (155°C trip, 15°C hysteresis), short-circuit protection, and a dedicated BP pin with 200kΩ internal resistor for 80Hz noise filtering via external 0.01µF capacitor. The MAX8878 variant adds active output discharge during shutdown via a 300Ω internal resistance path to GND.

Key Specifications

Pinout & Package

MAX8878EUK33+T is housed in a 5-pin SOT23-5 regular package (JEDEC MO-178AA), with exposed pad not electrically connected. The GND pin serves as both circuit return and primary thermal path; soldering to a large copper area improves power dissipation up to 571mW at +70°C ambient.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX8878EUK33+T, the MAX8877EUK33+T omits auto-discharge but matches all electrical and thermal specs, while the MCP1700T-3302E/MB trades noise performance, protection features, and pin count for lower unit cost and smaller footprint - making it suitable only where those compromises are acceptable.

Availability

MAX8878EUK33+T is available at Aetrix Electronics and suitable for cellular handsets, PCMCIA cards, hand-held instruments, and electronic planners requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for MAX8878EUK33+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 semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, communications, and consumer applications.

The MAX8877/MAX8878 product line was engineered for ultra-low-noise, low-quiescent-current regulation in portable battery-powered systems - targeting extended runtime, signal integrity, and robustness in space-constrained handheld electronics.

FAQ

What is the output voltage tolerance of the MAX8878EUK33+T over temperature and load?

The MAX8878EUK33+T delivers 3.3V output with ±1.4% accuracy across -40°C to +85°C ambient temperature and 0.1mA to 120mA load current. This specification is guaranteed per the datasheet's Electrical Characteristics table and applies to both regular and thin SOT23-5 packages. The MAX8878EUK33+T maintains this tolerance without external trimming or feedback components due to factory-trimmed internal resistor dividers.

Does the MAX8878EUK33+T require an external BP capacitor, and what happens if it is omitted?

Yes, the MAX8878EUK33+T 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 ADC references or RF sections. The BP pin connects to an internal 200kΩ resistor forming an 80Hz low-pass filter - essential for suppressing reference noise before error amplifier input.

How does the auto-discharge function work in the MAX8878EUK33+T during shutdown?

When the SHDN pin is pulled low, the MAX8878EUK33+T activates an internal 300Ω discharge path between OUT and GND, actively pulling the output voltage to ground within microseconds. This behavior is exclusive to the MAX8878 series (not present in MAX8877). The discharge path remains active until SHDN returns high, ensuring rapid, controlled output collapse - critical for safe power sequencing in multi-rail systems.

Can the MAX8878EUK33+T operate from a 2.5V input while delivering 3.3V output?

No - the MAX8878EUK33+T cannot regulate 3.3V output from a 2.5V input because the minimum input voltage must exceed the output voltage by the dropout voltage. With 165mV dropout at 150mA, the minimum valid input is 3.465V. At lighter loads (e.g., 50mA), dropout drops to 55mV, lowering the minimum input to 3.355V. Operation below V_OUT + V_DROP results in unregulated, pass-through behavior.

What thermal derating applies to the MAX8878EUK33+T in its SOT23-5 regular package?

The MAX8878EUK33+T in SOT23-5 regular package has a continuous power dissipation limit of 571mW at +70°C ambient, with thermal derating of 7.1mW/°C above that temperature. This assumes proper PCB layout: GND pin soldered to ≥100mm² copper area. Junction-to-board thermal resistance (θ_JB) is 140°C/W. Exceeding the +150°C absolute maximum junction temperature risks permanent damage or thermal shutdown activation.