25W/50W, Filterless, Spread-Spectrum, Stereo/Mono, Class D Amplifier

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The MAX9709 stereo/mono, Class D audio power amplifier delivers up to 2 x 25W into an 8Ω stereo mode and 1 x 50W into a 4Ω load in mono mode while offering up to 87% efficiency. The MAX9709 provides Class AB amplifier performance with the benefits of Class D efficiency, eliminating the need for a bulky heatsink and conserving power. The MAX9709 operates from a single +10V to +22V supply, driving the load in a BTL configuration.

The MAX9709 offers two modulation schemes: a fixed-frequency modulation (FFM) mode, and a spread-spectrum modulation (SSM) mode that reduces EMI-radiated emissions. The MAX9709 can be synchronized to an external clock from 600kHz to 1.2MHz. A synchronized output allows multiple units to be cascaded in the system.

Features include fully differential inputs, comprehensive click-and-pop suppression, and four selectable-gain settings (22dB, 25dB, 29.5dB, and 36dB). A pin-programmable thermal flag provides seven different thermal warning thresholds. Short-circuit and thermal-overload protection prevent the device from being damaged during a fault condition.

The MAX9709 is available in a 56-pin TQFN (8mm x 8mm x 0.8mm) package, and is specified over the extended -40°C to +85°C temperature range.
MAX9709: Simplilfied Block Diagram MAX9709: Simplilfied Block Diagram Enlarge+

Key Features

  • 2 x 25W Output Power in Stereo Mode (8Ω, THD = 10%)
  • 1 x 50W Output Power in Mono Mode (4Ω, THD = 10%)
  • High Efficiency: Up to 87%
  • Filterless Class D Amplifier
  • Unique Spread-Spectrum Mode
  • Programmable Gain (+22dB, +25dB, +29.5dB, +36dB)
  • High PSRR (90dB at 1kHz)
  • Differential Inputs Suppress Common-Mode Noise
  • Shutdown and Mute Control
  • Integrated Click-and-Pop Suppression
  • Low 0.1% THD+N
  • Current Limit and Thermal Protection
  • Programmable Thermal Flag
  • Clock Synchronization Input and Output
  • Available in Thermally Efficient, Space-Saving Package: 56-Pin TQFN


  • LCD TVs
  • PC/HiFi Audio Solutions
  • PDP TVs
Part NumberClassSpkr. Amp. VCC
Spkr. Amp. VCC
Spkr. Amp. ICC
POUT into 4Ω @ 1% THD+N
POUT into 4Ω @ 10% THD+N
POUT into 8Ω @ 1% THD+N
POUT into 8Ω @ 10% THD+N
Spkr. Amp. Half Pwr. THD+N
minmaxtypminminminminA- WeightedminSee Notes
MAX9709 D102220395019250.19590
$8.70 @1k
See All Speaker Amplifiers (33)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

MAX9709EVKIT: Evaluation Kit for the MAX9709

Technical Documents

App Note 3977 Class D Amplifiers: Fundamentals of Operation and Recent Developments
App Note 425

Quality and Environmental Data

Product Reliability Reports: MAX9709.pdf 
Lead-Free Package Tin (Sn) Whisker Reports

CAD Symbols and Footprints

  • MAX9709ETN+
  • MAX9709ETN+D
  • MAX9709ETN+TD
  • Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

    Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

    Quality Management System >
    Environmental Management System >


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