Analog Devices Inc./Maxim Integrated MAX1818EUT50#G16

Overview

The MAX1818EUT50#G16 from Maxim Integrated is a 500mA low-dropout linear regulator with preset 5.0V output, ±1% accuracy, 120mV dropout at full load, and 125µA ground current - designed for portable battery-powered systems requiring stable voltage under varying load and input conditions, such as USB hubs and notebook computer core logic rails.

For engineers reviewing the MAX1818EUT50#G16 datasheet, MAX1818EUT50#G16 pinout, MAX1818EUT50#G16 application, or MAX1818EUT50#G16 equivalent, key selection criteria include guaranteed 500mA output capability, active-low open-drain POK signal referenced to 93% of nominal VOUT, shutdown current below 0.1µA, thermal shutdown at +170°C, and compatibility with 1µF input / 3.3µF low-ESR output capacitors.

Technical Context

The MAX1818EUT50#G16 integrates a P-channel MOSFET pass transistor (R_DS(ON) ≈ 0.25Ω), 1.25V internal reference, error amplifier, and Dual Mode™ comparator that selects between factory-trimmed 5.0V regulation (SET tied to GND) or adjustable mode (via external resistor divider). Its architecture eliminates base-drive current loss typical of PNP regulators, enabling consistent 125µA ground current across load and dropout conditions.

It features an open-drain POK output asserting low when VOUT falls below 93% of 5.0V (i.e., 4.65V), a 0.1µA shutdown state with high-impedance OUT, thermal shutdown with 20°C hysteresis, and current limiting that increases from 0.8A (typ) to 1.6A (in-regulation) to handle transient loads without dropout-induced collapse.

Key Specifications

Pinout & Package

Package: RoHS-compliant 6-pin SOT23 (U6FH-6), 800mW power dissipation at +70°C ambient, requires IPC-JEDEC J-STD-020A reflow profile.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout linear regulator applications.

Compared with TPS76350DBVR and MCP1703T-5002E/MB, the MAX1818EUT50#G16 uniquely delivers 500mA at 120mV dropout with integrated POK and thermal hysteresis - making it suitable for higher-current, safety-critical portable 5V rails where reliability and headroom matter.

Availability

MAX1818EUT50#G16 is available at Aetrix Electronics and suitable for notebook computers, USB hubs, cellular telephones, docking stations, and base stations requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MAX1818EUT50#G16 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) designs precision analog, mixed-signal, and power management ICs for demanding industrial, automotive, and portable applications.

The MAX1818 series was developed specifically for battery-powered equipment needing high-output-current LDOs with ultra-low quiescent current, accurate fixed outputs, and integrated power monitoring - targeting PDA, cellular, and notebook power architectures.

FAQ

What output voltage does the MAX1818EUT50#G16 deliver, and is it adjustable?

The MAX1818EUT50#G16 delivers a factory-trimmed, non-adjustable 5.0V output with ±1% accuracy over -40°C to +85°C. It operates in preset mode when the SET pin is connected to GND. While the MAX1818 family supports adjustable outputs via external resistors, the MAX1818EUT50#G16 variant is specifically configured for fixed 5.0V operation - confirmed by its suffix "50" and top-mark "AANH"/"ABZL" in the Selector Guide.

Does the MAX1818EUT50#G16 include a power-good (POK) output, and how does it function?

Yes, the MAX1818EUT50#G16 includes an active-low open-drain POK output (Pin 2) that asserts low when VOUT drops below 93% of its nominal value - i.e., 4.65V for the 5.0V output. To generate a logic-high signal when regulation is valid, connect a 100kΩ pull-up resistor from POK to OUT. The POK output remains low during shutdown, providing unambiguous power-status signaling for microcontrollers in systems using the MAX1818EUT50#G16.

What is the maximum continuous output current and dropout voltage specification for the MAX1818EUT50#G16?

The MAX1818EUT50#G16 guarantees 500mA RMS output current with a typical dropout voltage of 120mV at 500mA load (measured as VIN – VOUT when VOUT is 100mV below nominal). This enables operation with input as low as 5.12V while maintaining 5.0V output - critical for extending usable battery voltage range in portable devices powered by the MAX1818EUT50#G16.

How does the MAX1818EUT50#G16 behave during thermal overload, and what protection mechanisms are built in?

When the junction temperature of the MAX1818EUT50#G16 exceeds +170°C, thermal shutdown activates and turns off the pass transistor. After the die cools by 20°C (to ~+150°C), the device automatically resumes regulation - resulting in pulsed output during sustained overload. This hysteresis prevents latch-up and enables safe, self-recovering operation. Combined with short-circuit current limiting (0.55–1.8A), this protects both the MAX1818EUT50#G16 and downstream circuitry.

What are the recommended input and output capacitors for stable operation of the MAX1818EUT50#G16?

For stable operation, the MAX1818EUT50#G16 requires a 1µF ceramic capacitor between IN and GND, and a 3.3µF low-ESR (≤0.1Ω) ceramic capacitor between OUT and GND. These values ensure stability across temperature and load (up to 500mA). For output voltages below 2.0V, a 4.7µF output capacitor is specified - but not required for the 5.0V MAX1818EUT50#G16. Placement must be adjacent to the pins to minimize trace inductance.