Analog Devices Inc./Maxim Integrated MAX8891EXK45+T

Overview

MAX8891EXK45+T from Maxim Integrated is a fixed-output, low-dropout linear regulator delivering 4.5V at up to 150mA with 120mV dropout at 120mA load, 40µA ground current, and 65dB PSRR at 10kHz - designed for space-constrained battery-powered systems such as portable radios and digital cameras.

For engineers reviewing the MAX8891EXK45+T datasheet, MAX8891EXK45+T pinout, MAX8891EXK45+T application, or MAX8891EXK45+T equivalent, key selection criteria include guaranteed 150mA output capability, stability with only 1µF ceramic capacitors, SC70 package footprint constraints, and shutdown current below 1µA.

Technical Context

The MAX8891EXK45+T employs a p-channel MOSFET series pass transistor with 1Ω typical R_DS(ON), enabling low dropout and eliminating base-drive current loss. Its bandgap reference (1.225V) feeds an error amplifier that controls gate voltage to maintain regulation under varying load and line conditions.

It integrates overcurrent protection (200mA limit), thermal shutdown at +160°C with 10°C hysteresis, and logic-level shutdown control (SHDN active-low). The device operates across 2V–6V input and requires no external feedback components due to its factory-preset 4.5V output.

Key Specifications

Pinout & Package

MAX8891EXK45+T is housed in a 5-pin SC70 package (2.0mm × 1.25mm × 0.9mm), optimized for ultra-compact layouts. Thermal performance relies on GND pin connection to a large copper pour for heat dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX8891EXK45+T, the XC6206P452MR offers lower quiescent current but sacrifices dropout performance, while the AP2112K-4.5TRG1 provides higher current headroom at the cost of larger footprint and reduced PSRR - making MAX8891EXK45+T optimal for size- and noise-sensitive 150mA applications.

Availability

MAX8891EXK45+T is available at Aetrix Electronics and suitable for Bluetooth portable radios, digital cameras, personal stereos, portable medical monitors, and cordless phone subsystems requiring stable component supply with RoHS-compliant packaging and industrial temperature support.

Supply support for MAX8891EXK45+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 MAX8891/MAX8892 product line was engineered for ultra-compact, low-noise power regulation in battery-powered portable electronics - emphasizing minimal external components, low quiescent current, and robust thermal and overload protection.

FAQ

What is the output voltage tolerance of the MAX8891EXK45+T?

The MAX8891EXK45+T has a guaranteed output voltage accuracy of ±3% over temperature (-40°C to +85°C) and load (100μA to 80mA). This specification ensures reliable operation for 4.5V-tolerant logic and analog circuits without requiring post-production calibration. The MAX8891EXK45+T achieves this using a precision 1.225V bandgap reference and trimmed internal feedback divider.

Does the MAX8891EXK45+T require external feedback resistors?

No, the MAX8891EXK45+T does not require external feedback resistors. It is a factory-preset LDO with a fixed 4.5V output implemented via internal resistor division. Unlike the adjustable MAX8892 variant, the MAX8891EXK45+T uses pins 1 (IN), 2 (GND), 3 (SHDN), 4 (N.C.), and 5 (OUT) - with pin 4 left unconnected - simplifying layout and reducing BOM count.

What is the minimum input voltage needed for regulation with the MAX8891EXK45+T?

The minimum input voltage for regulation is determined by dropout: at 120mA load, the MAX8891EXK45+T requires VIN ≥ 4.62V (4.5V + 120mV). At lighter loads, dropout decreases - e.g., ~50mV at 25mA - allowing operation down to ~4.55V. The absolute minimum input is 2V, but regulation is only maintained above VOUT + dropout voltage.

Can the MAX8891EXK45+T be used with X5R or Y5V ceramic capacitors?

The MAX8891EXK45+T is guaranteed stable with 1µF X7R or X5R ceramic capacitors across the full -40°C to +85°C range. For Y5V or Z5U dielectrics - which exhibit significant capacitance loss and ESR increase at low temperatures - a 2.2µF or larger output capacitor is recommended to maintain stability below -10°C, per the manufacturer's capacitor selection guidelines.

How does thermal shutdown operate in the MAX8891EXK45+T?

The MAX8891EXK45+T activates thermal shutdown when junction temperature exceeds +160°C, turning off the pass transistor. After cooling by 10°C (to +150°C), it automatically resumes regulation - resulting in pulsed output during sustained overload. This self-recovering behavior protects the MAX8891EXK45+T without requiring external intervention or latch-off circuitry.