Analog Devices Inc./Maxim Integrated MAX1857EUA47+T

Overview

MAX1857EUA47+T from Maxim Integrated is a 500mA, low-dropout linear regulator with ±1% output voltage accuracy preset at 4.75V, 120mV dropout at full load, 135µA ground current, and integrated active-low open-drain reset output with 4.5ms timeout-designed for stable power delivery in space-constrained portable systems such as notebook computers and cellular handsets.

For engineers reviewing the MAX1857EUA47+T datasheet, MAX1857EUA47+T pinout, MAX1857EUA47+T application, or MAX1857EUA47+T equivalent, this page delivers verified electrical parameters, µMAX package layout, reset timing behavior, thermal shutdown thresholds, and real-world LDO selection criteria including dropout vs. load, PSRR performance, and capacitor stability requirements.

Technical Context

The MAX1857EUA47+T integrates a 1.25V internal reference, error amplifier, and 0.25Ω P-channel MOSFET pass transistor to achieve ultra-low quiescent current independent of load. Its Dual Mode™ architecture selects between factory-trimmed 4.75V regulation (SET = GND) or adjustable output (1.25V–5.0V) via external resistor divider on the SET pin.

It features an open-drain RST output that asserts low when VOUT falls below 86% of nominal (4.04V), holds for ≥4.5ms after recovery, and requires external 100kΩ pullup to OUT. Thermal shutdown activates at +170°C with 20°C hysteresis, and short-circuit protection limits output current to 1.2A (2.0A near regulation).

Key Specifications

Pinout & Package

MAX1857EUA47+T is housed in an 8-pin µMAX package (3mm × 3mm, 0.5mm pitch), thermally enhanced with exposed pad for improved power dissipation in compact layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS763475DBVR and MCP1825-4702E/DB, the MAX1857EUA47+T uniquely combines 4.75V precision, ultra-low dropout, integrated reset with programmable delay, and thermal hysteresis-making it optimal for portable electronics requiring guaranteed power sequencing and extended battery life under dynamic loads.

Availability

MAX1857EUA47+T is available at Aetrix Electronics and suitable for notebook computers, cellular telephones, and PDAs requiring stable component supply, long-term lifecycle support, and guaranteed parametric compliance across industrial temperature range (-40°C to +85°C).

Supply support for MAX1857EUA47+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 demanding industrial, automotive, and portable applications.

The MAX1857 belongs to Maxim's low-dropout regulator product line, engineered specifically for battery-powered systems needing high accuracy, low quiescent current, and integrated power-good signaling in minimal footprint.

FAQ

What is the guaranteed output voltage accuracy of the MAX1857EUA47+T over temperature?

The MAX1857EUA47+T guarantees ±1% output voltage accuracy over the full operating temperature range of -40°C to +85°C, with typical deviation of ±0.5% at +25°C. This specification applies to the factory-trimmed 4.75V output in preset mode (SET = GND) and is confirmed across all production lots per Maxim's datasheet revision 0.

Does the MAX1857EUA47+T support adjustable output voltage, and if so, what is the range?

Yes, the MAX1857EUA47+T supports adjustable output voltage via its SET pin. When configured with an external resistive divider, the output can be set from 1.25V to 5.0V. The internal 1.25V reference and Dual Mode™ comparator enable seamless transition between preset 4.75V operation and adjustable mode based on SET pin voltage threshold (50–150mV).

What is the function and timing behavior of the RST pin on the MAX1857EUA47+T?

The RST pin on the MAX1857EUA47+T is an active-low, open-drain reset output that asserts low when VOUT falls below 86% of nominal (4.04V). After VOUT recovers above threshold, RST remains low for a guaranteed 4.5ms release delay before going high-impedance. It requires a 100kΩ pullup resistor to OUT and is commonly used as a power-on-reset signal for microcontrollers.

What thermal protection features does the MAX1857EUA47+T include, and how do they behave?

The MAX1857EUA47+T incorporates thermal shutdown that activates at +170°C junction temperature and releases at +150°C (20°C hysteresis). During continuous overload, this causes pulsed output operation rather than latch-up. The device also includes short-circuit current limiting (1.2A typical, 2.0A near regulation) and indefinite short-to-ground tolerance without damage.

Can the MAX1857EUA47+T operate from a 2.7V input while delivering 500mA at 4.75V output?

No-the MAX1857EUA47+T cannot sustain 500mA at 4.75V output from a 2.7V input. Its minimum input voltage is constrained by dropout: VIN ≥ VOUT + VDROPOUT. With 120mV typical dropout, minimum VIN = 4.87V. At 2.7V input, the device enters dropout and cannot regulate 4.75V; maximum deliverable output would be ~2.58V (2.7V – 120mV), well below nominal.