Analog Devices Inc./Maxim Integrated MAX8840ELT31+T

Overview

MAX8840ELT31+T from Maxim Integrated is a 3.1V 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 rails in portable RF systems.

For engineers reviewing the MAX8840ELT31+T datasheet, MAX8840ELT31+T pinout, MAX8840ELT31+T application, or MAX8840ELT31+T equivalent, key selection criteria include guaranteed 3.1V output accuracy (±3%), sub-1µA shutdown current, stability with 1µF ceramic output capacitor, and µDFN-6 package compatibility with space-constrained battery-powered designs.

Technical Context

The MAX8840ELT31+T uses an internal 1.225V bandgap reference 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 a 10nF capacitor to shunt high-frequency noise from the error amplifier's bias network, directly enabling the 11µV_RMS noise performance.

Shutdown logic disables the voltage reference, error amplifier, gate driver, and pass transistor when SHDN is pulled low, reducing supply current to <1µA. Thermal protection activates at +160°C junction temperature with 10°C hysteresis, forcing pulsed operation under sustained overload without damage.

Key Specifications

Pinout & Package

MAX8840ELT31+T is housed in a 1.5mm × 1.0mm × 0.8mm lead-free µDFN-6 package with exposed thermal pad (pin 5 is N.C., not internally connected). The package is optimized for thermal dissipation through the GND pin and bottom-side thermal pad soldered to PCB ground plane.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-noise LDO applications.

Compared with XC6219B312MR-G and ADP160ACBZ-3.1-R7, the MAX8840ELT31+T delivers the lowest output noise (11µV_RMS) and smallest package (1.5mm × 1.0mm), making it uniquely suited for next-generation miniaturized RF and audio subsystems where noise floor and board area are co-constrained.

Availability

MAX8840ELT31+T is available at Aetrix Electronics and suitable for Bluetooth radios, wireless LAN baseband processors, portable digital camera sensors, and personal stereo DAC reference supplies requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for MAX8840ELT31+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 applications.

The MAX8840 family was designed specifically for ultra-low-noise, space-constrained power delivery in portable RF and audio systems - prioritizing noise performance, small footprint, and minimal external components over general-purpose flexibility.

FAQ

What is the maximum input voltage rating for MAX8840ELT31+T?

The MAX8840ELT31+T has an absolute maximum input voltage of +7V relative to GND. However, its operational input range is specified from 2V to 6V. Exceeding 6V may cause excessive power dissipation or violate safe operating area limits, especially at elevated temperatures. Always maintain VIN ≤ 6V in normal operation to ensure reliability and meet datasheet performance guarantees for the MAX8840ELT31+T.

Does MAX8840ELT31+T require an external feedback resistor network?

No, the MAX8840ELT31+T does not require an external feedback resistor network. It is a factory-preset 3.1V output regulator with internal feedback divider. Only the MAX8842 variant supports adjustable output via FB pin; the MAX8840ELT31+T uses fixed internal resistors and has no FB pin - simplifying design and reducing component count for the MAX8840ELT31+T.

Can MAX8840ELT31+T operate stably with a 0.47µF output capacitor?

No, the MAX8840ELT31+T is not guaranteed stable with 0.47µF output capacitance. The datasheet specifies stability with ≥1µF ceramic capacitor (X5R/X7R dielectric). Using 0.47µF risks oscillation or degraded transient response, particularly at temperature extremes or high load currents. Always use ≥1µF for reliable operation of the MAX8840ELT31+T.

What is the purpose of the BP pin on MAX8840ELT31+T?

The BP (Bypass) pin on the MAX8840ELT31+T connects to a 10nF capacitor between BP and OUT to shunt high-frequency noise from the error amplifier's bias current, enabling the ultra-low 11µV_RMS output noise specification. This pin is unique to the MAX8840 variant and is not present on MAX8841/MAX8842. Omitting the BP capacitor degrades noise performance of the MAX8840ELT31+T significantly.

Is MAX8840ELT31+T RoHS-compliant and lead-free?

Yes, the "+T" suffix in MAX8840ELT31+T indicates a lead-free, RoHS-compliant package. The device uses a µDFN-6 package with matte tin finish and conforms to JEDEC J-STD-020 moisture sensitivity level 1 (MSL1), allowing standard reflow soldering without special handling. All Maxim Integrated parts with "+" suffix meet current RoHS directives for the MAX8840ELT31+T.