Analog Devices Inc./Maxim Integrated MAX1818EUT18+T

Overview

MAX1818EUT18+T from Maxim Integrated is a 500mA low-dropout linear regulator with preset 1.8V output, ±1% accuracy over temperature, 120mV dropout at full load, and integrated power-ok (POK) open-drain output. It features an internal PMOS pass transistor, 125μA ground current independent of load, and operates from 2.5V to 5.5V input - designed for power rail regulation in portable battery-powered systems such as cellular phones and notebook computers.

For engineers reviewing the MAX1818EUT18+T datasheet, MAX1818EUT18+T pinout, MAX1818EUT18+T application, or MAX1818EUT18+T equivalent, key selection criteria include guaranteed 500mA output under dropout conditions, 0.1μA shutdown current, thermal and short-circuit protection, and SOT23-6 package compatibility with space-constrained PCB layouts.

Technical Context

The MAX1818EUT18+T uses an internal 1.25V reference and error amplifier to regulate output via a 0.25Ω P-channel MOSFET pass transistor - eliminating base-drive current and enabling stable 125μA quiescent current across load and dropout conditions. Its Dual Mode™ architecture selects between factory-trimmed 1.8V output (SET = GND) or adjustable mode (SET biased externally).

Power-OK (POK) monitoring compares VOUT against 93% of nominal voltage with hysteresis, asserting low when out-of-regulation; shutdown logic disables the pass transistor and forces POK low while reducing supply current to 0.1μA. Thermal shutdown activates at +170°C with 20°C hysteresis, and current limiting provides 0.8A typical short-circuit protection.

Key Specifications

Pinout & Package

MAX1818EUT18+T is housed in a RoHS-compliant 6-pin SOT23-6 package (U6FH-6 outline), rated for 800mW power dissipation at +70°C with 10mW/°C derating above that temperature. The package requires IPC/JEDEC J-STD-020A-compliant reflow only; hand or wave soldering is prohibited due to specialized thermal profile constraints.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS76318DBVR and MCP1700T-1802E/TT, MAX1818EUT18+T delivers 2× higher output current, 40% lower dropout at full load, integrated POK signaling, and robust thermal cycling behavior - making it suitable for demanding portable systems requiring both performance headroom and system-level fault visibility.

Availability

MAX1818EUT18+T is available at Aetrix Electronics and suitable for cellular telephones, notebook computers, and USB hubs requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX1818EUT18+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) designs precision analog, mixed-signal, and power-management ICs for industrial, automotive, communications, and consumer applications.

The MAX1818 series is engineered for battery-powered portable electronics, emphasizing ultra-low quiescent current, low dropout, and integrated system-monitoring functions like POK and thermal protection.

FAQ

What is the guaranteed output voltage accuracy of the MAX1818EUT18+T over temperature?

The MAX1818EUT18+T guarantees ±2.5% output voltage accuracy over the full -40°C to +85°C operating temperature range at 100mA load. At +25°C and 100mA, accuracy tightens to ±1%. This specification applies specifically to the factory-preset 1.8V version and is confirmed in the Electrical Characteristics table of the official datasheet.

Does the MAX1818EUT18+T require external resistors to set its 1.8V output?

No, the MAX1818EUT18+T does not require external resistors for its 1.8V output. The "18" suffix indicates factory-trimmed 1.8V operation, activated by connecting the SET pin to GND. External resistors are only needed if using the adjustable mode (1.25V–5.0V), which is not the default configuration for MAX1818EUT18+T.

What is the maximum continuous output current supported by the MAX1818EUT18+T?

The MAX1818EUT18+T guarantees 500mA RMS output current under specified conditions: VIN ≥ 2.7V, ambient temperature ≤ +85°C, and proper PCB copper layout. Derating applies above +70°C ambient (10mW/°C), and actual deliverable current depends on VIN–VOUT differential and thermal design - see Figure 3 in the datasheet for voltage-dependent limits.

Can the MAX1818EUT18+T be used with ceramic output capacitors?

Yes, the MAX1818EUT18+T is fully compatible with ceramic output capacitors. It requires a minimum 3.3µF low-ESR (≤0.1Ω) capacitor on the OUT pin; surface-mount ceramics meeting this ESR spec are explicitly recommended in the datasheet for optimal stability and transient response.

What is the function of the POK pin on the MAX1818EUT18+T, and how should it be interfaced?

The POK pin on the MAX1818EUT18+T is an open-drain output that goes low when VOUT falls below 93% of 1.8V (i.e., <1.674V). To interface, connect a 100kΩ pull-up resistor from POK to OUT. This generates a logic-high signal when regulation is valid and pulls low during undervoltage - enabling direct connection to microcontroller reset or interrupt inputs without additional level-shifting circuitry.