Analog Devices Inc./Maxim Integrated MAX8840ELT18+T

Overview

MAX8840ELT18+T from Maxim Integrated is a 1.8V fixed-output, ultra-low-noise, high-PSRR, low-dropout linear regulator delivering up to 150mA output current with 120mV dropout at 120mA load, 11µV_RMS output noise (100Hz–100kHz), and 78dB PSRR at 1kHz. It employs a p-channel MOSFET pass transistor, operates from 2V–6V input, and targets noise-sensitive analog/RF power rails in portable electronics.

For engineers reviewing the MAX8840ELT18+T datasheet, MAX8840ELT18+T pinout, MAX8840ELT18+T application, or MAX8840ELT18+T equivalent, key selection criteria include its 1.8V preset output, µDFN-6 package footprint, sub-1µA shutdown current, stability with 1µF ceramic output capacitor, and BP-pin–enabled noise reduction architecture.

Technical Context

The MAX8840ELT18+T uses an integrated bandgap reference (1.225V) and error amplifier to regulate output via a 1Ω (typ) p-channel MOSFET pass transistor, eliminating base-drive current and enabling ultra-low ground current (40µA typical). Its BP pin connects to an external 10nF capacitor to shunt high-frequency noise from the internal reference path, directly enabling the 11µV_RMS noise performance.

Shutdown is controlled by a logic-compatible SHDN pin (0.4V low threshold, 1.5V high threshold) that disables the reference, error amplifier, gate driver, and pass transistor-reducing supply current to <1µA and placing OUT in high-impedance state. Thermal shutdown activates at +160°C with 10°C hysteresis, and overcurrent protection limits output to 150–300mA depending on conditions.

Key Specifications

Pinout & Package

MAX8840ELT18+T is housed in a 1.0mm × 1.5mm × 0.8mm, 6-pin µDFN package with exposed thermal pad (pin 2 = GND). The package is RoHS-compliant and lead-free ("+T" suffix).

Key Features

Applications

Equivalent & Alternatives

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

Compared with the Torex XC6219B182MR-G and Analog Devices ADP125ARHZ-1.8-R7, the MAX8840ELT18+T delivers superior noise performance (11µV_RMS vs. ≥40µV_RMS) and smaller footprint (1.0mm × 1.5mm vs. ≥2mm²), making it optimal for space-constrained, noise-critical 1.8V rails despite its 150mA limit.

Availability

MAX8840ELT18+T is available at Aetrix Electronics and suitable for cellular handsets, Bluetooth accessories, digital cameras, and portable medical monitors requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for MAX8840ELT18+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 markets.

The MAX8840 series belongs to Maxim's ultra-low-noise LDO product line, engineered specifically for powering noise-sensitive RF, audio, and precision analog circuitry in battery-operated portable equipment.

FAQ

What is the maximum output current capability of the MAX8840ELT18+T?

The MAX8840ELT18+T is guaranteed to deliver 150mA continuous output current under all operating conditions. Electrical characteristics specify a minimum current limit of 150mA and a maximum of 300mA, with thermal and overcurrent protection ensuring safe operation even under sustained overload or short-circuit conditions. This makes the MAX8840ELT18+T suitable for moderate-power analog and digital loads in portable systems.

Does the MAX8840ELT18+T require an external bypass capacitor for low-noise operation?

Yes-the MAX8840ELT18+T requires a 10nF capacitor connected between the BP pin and OUT to achieve its specified 11µV_RMS output noise. This capacitor forms part of an internal noise-bypass network that filters reference voltage noise. Omitting it degrades noise performance to ~230µV_RMS, per datasheet comparisons with MAX8841/MAX8842 variants. The capacitor must be placed close to the device with minimal trace length.

What is the dropout voltage of the MAX8840ELT18+T at full load?

The MAX8840ELT18+T exhibits a dropout voltage of 120mV at 120mA load current, measured at room temperature. At 150mA, dropout increases slightly but remains below 180mV for VOUT ≥ 2.5V. This low dropout enables operation from input voltages as low as 1.92V, maximizing usable capacity from single-cell lithium batteries and supporting longer runtime in portable applications.

Can the MAX8840ELT18+T be used with ceramic output capacitors?

Yes-the MAX8840ELT18+T is explicitly designed and tested for stability with 1µF ceramic output capacitors using X7R or X5R dielectrics across the full −40°C to +85°C temperature range. Larger values improve transient response and PSRR, but 1µF is the minimum required for guaranteed stability. Z5U/Y5V dielectrics may require ≥2.2µF at low temperatures to maintain phase margin.

How does the shutdown function operate on the MAX8840ELT18+T?

The MAX8840ELT18+T enters ultra-low-power shutdown mode when the SHDN pin is pulled below 0.4V (logic low), reducing supply current to less than 1µA and placing the OUT pin in high-impedance state. Exit delay is typically 300µs. SHDN must be driven with a logic signal or pulled to IN for normal operation; its input bias current is ≤0.1µA, enabling direct interface with low-drive GPIOs without loading.