20-W stereo Class D amplifier

20-W stereo Class D speaker amp runs over 4.5 to 14 V, for the first time

Eliminates the need for bulky LC filters, minimizes cost and size of portable devices

The 20-W MAX9744 stereo Class D speaker amplifier is claimed the first to operate from a 4.5 to 14-V power supply. Its wide supply range minimizes the cost of portable designs by reducing component count and allowing the use of a smaller battery pack.


Additionally, the device integrates 64-step analog and digital volume control. External feedback resistors set the input gain, while the output has an internally set gain. When powered from a 12-V supply, the device combines these gains with the wide volume-control range, and delivers 20-W per channel into 4-Ω speakers.

Specifications include 93% efficiency, 75-dB PSRR, a 0.04% THD+N, and greater than 90-dB SNR. The amplifier employs the company’s spread-spectrum modulation to reduce the peaks of the fundamental and subsequent harmonics by spreading energy over a wider bandwidth. This device also offers a filterless modulation mode.
Available in a 7 x 7 x 0.8-mm, 44-pin TQFN, the MAX9744 also includes a low-power shutdown mode, a mute function, and integrated click-and-pop suppression. (From $2.45 ea/1,000 available now.) Maxim Integrated Products, Sunnyvale, CA
Customer Service 888-629-4642
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