Analog Devices Inc./Maxim Integrated MAX8840ELT40+T

Overview

MAX8840ELT40+T from Maxim Integrated is a preset 4.0V, 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 - designed for powering noise-sensitive analog circuitry in portable RF systems.

For engineers reviewing the MAX8840ELT40+T datasheet, MAX8840ELT40+T pinout, MAX8840ELT40+T application, or MAX8840ELT40+T equivalent, key selection criteria include guaranteed 4.0V output accuracy (±3%), µDFN-6 package compatibility, 40µA ground current at light load, shutdown current <1µA, and stability with 1µF ceramic output capacitor.

Technical Context

The MAX8840ELT40+T employs a p-channel MOSFET pass transistor (typ. R_DS(ON) = 1Ω) enabling low quiescent current and minimal dropout voltage dependence on load. Its bandgap reference (1.225V) feeds an error amplifier that controls gate drive to maintain regulation without base-drive losses typical of bipolar designs.

Noise performance is enhanced by a dedicated BP pin connected to a 10nF bypass capacitor, which shunts high-frequency noise from the internal reference and error amplifier. Shutdown logic disables the reference, error amp, and gate driver, reducing supply current to <0.05µA at +85°C.

Key Specifications

Pinout & Package

MAX8840ELT40+T is housed in a 1.5mm × 1.0mm × 0.8mm, 6-pin µDFN package with exposed thermal pad (pin 5 is N.C., not internally connected). The package supports high-density layout and efficient heat dissipation via GND pin thermal conduction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B402MR-G and ADP125ARHZ-4.0-R7, the MAX8840ELT40+T uniquely delivers 11µV_RMS noise in a 1.5mm × 1.0mm footprint with 120mV dropout - making it optimal for RF-sensitive, size-limited, battery-powered systems where noise and efficiency are co-critical.

Availability

MAX8840ELT40+T is available at Aetrix Electronics and suitable for cellular front-end power, portable audio codec supply, Bluetooth LE sensor node, industrial wireless transmitter, and other applications requiring stable component supply with guaranteed long-term availability.

Supply support for MAX8840ELT40+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-critical analog sections in portable RF and audio systems where PSRR, dropout, and output stability are non-negotiable.

FAQ

What is the exact output voltage tolerance of MAX8840ELT40+T over temperature and load?

The MAX8840ELT40+T guarantees ±3% output voltage accuracy across the full -40°C to +85°C operating temperature range and for load currents from 100µA to 80mA. At +25°C and 1mA load, the tolerance tightens to ±1%. This specification is 100% tested and applies directly to the MAX8840ELT40+T device, ensuring consistent 4.0V regulation in production environments.

Does MAX8840ELT40+T require an external bypass capacitor, and what value is recommended?

Yes, the MAX8840ELT40+T requires a 10nF capacitor between the BP pin and OUT pin to achieve its specified 11µV_RMS output noise. This capacitor is mandatory for ultra-low-noise operation and must be placed as close as possible to the BP and OUT pins. Values outside 0.001µF–0.1µF are not recommended, as they degrade noise performance or stability.

Can MAX8840ELT40+T operate with input voltages below 4.0V?

Yes, the MAX8840ELT40+T can operate with input voltages as low as 4.12V under 120mA load (120mV dropout), and down to ~4.05V at lighter loads. Its minimum input voltage is 2V, but regulation is only maintained when VIN ≥ VOUT + dropout voltage. Below dropout, the output follows the input minus R_DS(ON) × I_LOAD.

Is the MAX8840ELT40+T compatible with standard 1µF ceramic output capacitors?

Yes, the MAX8840ELT40+T is fully stable with a single 1µF X5R or X7R ceramic capacitor on the output - no additional ESR or capacitance is required. This is verified across temperature and load, eliminating need for larger or specialized capacitors and simplifying layout in space-constrained designs.

What thermal considerations apply to MAX8840ELT40+T in continuous 150mA operation?

In continuous 150mA operation at VIN = 5.5V and VOUT = 4.0V, power dissipation is 225mW. With θ_JA = 477°C/W, junction temperature rise is ~107°C above ambient. To stay within the +150°C absolute max junction rating, ambient must remain ≤ +43°C unless enhanced PCB thermal design (e.g., 2oz copper, thermal vias under GND pad) is implemented for the MAX8840ELT40+T.