Analog Devices Inc./Maxim Integrated MAX1818ESA20

Overview

MAX1818ESA20 from Maxim Integrated is a 500mA low-dropout linear regulator with ±1% output voltage accuracy, 120mV dropout at full load, and 125µA ground current. It features an internal PMOS pass transistor, active-low open-drain POK output, and shutdown current of 0.1µA. Designed for portable battery-powered systems, it delivers stable 2.0V output from 2.5V–5.5V input in a 6-pin SOT23 package.

For engineers reviewing the MAX1818ESA20 datasheet, MAX1818ESA20 pinout, MAX1818ESA20 application, or MAX1818ESA20 equivalent, key selection criteria include guaranteed 500mA output under low-input-headroom conditions, preset 2.0V output with no external resistors, thermal and short-circuit protection, and compatibility with compact PCB layouts requiring minimal bypass capacitance.

Technical Context

The MAX1818ESA20 uses a P-channel MOSFET pass transistor with 0.25Ω R_DS(ON), enabling low dropout and load-independent quiescent current. Its Dual Mode™ architecture selects between factory-trimmed 2.0V output (SET grounded) and adjustable mode (SET connected to external divider), with V_SET threshold at 50–150mV.

Regulation relies on a 1.25V internal reference and error amplifier comparing feedback against that reference. The POK output asserts low when V_OUT falls below 93% of nominal (1.86V), and thermal shutdown activates at +170°C with 20°C hysteresis.

Key Specifications

Pinout & Package

MAX1818ESA20 is housed in a RoHS-compliant 6-pin SOT23 package (package code U6FH-6), rated for 800mW power dissipation at +70°C ambient with appropriate PCB copper area.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS76320QDBVRQ1 and MCP1702T-2002E/MB, MAX1818ESA20 uniquely combines 500mA output, 120mV dropout, and 125µA ground current in a 6-pin SOT23 - making it optimal for space-constrained, battery-powered systems demanding both high current and ultra-low quiescent power.

Availability

MAX1818ESA20 is available at Aetrix Electronics and suitable for notebook computers, cellular telephones, and USB hubs requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX1818ESA20 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 MAX1818ESA20 belongs to Maxim's low-dropout linear regulator product line, engineered specifically for portable battery-operated equipment where minimal dropout, ultra-low quiescent current, and small footprint are essential design requirements.

FAQ

What output voltage does the MAX1818ESA20 deliver?

The MAX1818ESA20 delivers a factory-trimmed, fixed 2.0V output with ±1% accuracy over the full -40°C to +85°C operating temperature range. This preset voltage is achieved by grounding the SET pin; no external resistors are required. The device also supports adjustable operation (1.25V–5.0V) when SET is connected to an external resistor divider, but the ESA20 suffix specifically denotes the 2.0V variant.

Does the MAX1818ESA20 require external capacitors for stable operation?

Yes, the MAX1818ESA20 requires two external capacitors: a 1µF ceramic capacitor between IN and GND, and a 3.3µF low-ESR (≤0.1Ω) ceramic capacitor between OUT and GND. These components ensure loop stability, reduce output noise, and improve load-transient response. For 2.0V output, the standard 3.3µF value is sufficient; a 4.7µF capacitor is recommended only for outputs below 2.0V.

How does the POK output function on the MAX1818ESA20?

The POK (Power OK) output on the MAX1818ESA20 is an open-drain N-channel signal that pulls low when the regulated output falls below 93% of nominal (i.e., below 1.86V for the 2.0V version). When V_OUT rises above this threshold, POK goes high-impedance. To interface with logic inputs, a 100kΩ pull-up resistor from POK to OUT is required. During shutdown, POK is actively held low regardless of output voltage.

What thermal protection features does the MAX1818ESA20 include?

The MAX1818ESA20 incorporates thermal shutdown protection that disables the pass transistor when junction temperature exceeds +170°C. After shutdown, the device remains off until the junction cools by 20°C (to +150°C), at which point regulation resumes automatically. This auto-recovering behavior prevents permanent damage during temporary overloads or inadequate PCB heatsinking, and complements the 800mW power dissipation rating of its SOT23 package.

Can the MAX1818ESA20 operate with a 2.5V input supplying a 2.0V output?

Yes, the MAX1818ESA20 can operate with a 2.5V input supplying a 2.0V output because its guaranteed dropout voltage is 120mV at 500mA. With a 2.5V input, the minimum sustainable output is 2.5V − 0.12V = 2.38V under worst-case conditions - however, actual typical dropout is 120mV, so 2.5V input supports stable 2.0V output with 300mV headroom. The device's absolute minimum input is specified as 2.5V, aligning precisely with this use case.