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80mW, DirectDrive, Stereo Headphone Amplifier with Common-Mode Sense

80mW, DirectDrive, Stereo Headphone Amplifier with Common-Mode Sense

Product Details

Key Features

Simplified Block Diagram

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Key Features

  • No Bulky DC-Blocking Capacitors Required
  • Ground-Referenced Outputs Eliminate DC-Bias Voltages on Headphone Ground Pin
  • Common-Mode Voltage Sensing Eliminates Ground-Loop Noise
  • 96dB CMRR
  • No Degradation of Low-Frequency Response Due to Output Capacitors
  • 80mW per Channel into 16Ω
  • Low 0.002% THD+N
  • High 86dB PSRR
  • Integrated Click-and-Pop Suppression
  • 1.8V to 3.6V Single-Supply Operation
  • Low Quiescent Current
  • Low-Power Shutdown Mode
  • Short-Circuit and Thermal-Overload Protection
  • ±8kV ESD-Protected Amplifier Outputs
  • Available in a Space-Saving Package
    • 20-Pin Thin QFN (4mm x 4mm x 0.8mm)

Applications/Uses

  • Cell Phones
  • Desktop PCs
  • MP3 Players
  • Notebook Computers
  • PDAs
  • Portable Audio Equipment
  • Tablet PCs

Description

The MAX4409 stereo headphone amplifier combines Maxim's DirectDrive® architecture and a common-mode sense input, which allows the amplifier to reject common-mode noise. Conventional headphone amplifiers require a bulky DC-blocking capacitor between the headphone and the amplifier. DirectDrive produces a ground-referenced output from a single supply, eliminating the need for large DC-blocking capacitors, which saves cost, board space, and component height. The common-mode voltage sensing corrects for any difference between SGND of the amplifier and the headphone return. This feature minimizes ground-loop noise when the HP socket is used as a line out connection to other grounded equipment, for example, a PC connected to a home hi-fi system.

The MAX4409 draws only 5mA of supply current, delivers up to 80mW per channel into a 16Ω load, and has a low 0.002% THD+N. A high 86dB power-supply rejection ratio allows this device to operate from noisy digital supplies without additional power-supply conditioning. The MAX4409 includes ±8kV ESD protection on the headphone outputs. Comprehensive click-and-pop circuitry eliminates audible clicks and pops on startup and shutdown. A low-power shutdown mode reduces supply current draw to only 6µA.

The MAX4409 operates from a single 1.8V to 3.6V supply, has short-circuit and thermal overload protection, and is specified over the extended -40°C to +85°C temperature range. The MAX4409 is available in a tiny 20-pin thin QFN (4mm x 4mm x 0.8mm) package.

Simplified Block Diagram

MAX4409: Typical Application Circuit MAX4409: Typical Application Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .