20W Stereo Class D Speaker Amplifier with Analog and Digital Volume Control Operates from a 4.5V to 14V Supply
Note to Editor:
- The MAX9744 is a 20W stereo Class D speaker amplifier with analog and digital volume control.
- The industry's only stereo Class D amplifier to operate from a 4.5V to 14V supply, this device minimizes the cost and size of portable designs.
- Integrated spread-spectrum, filterless modulation eliminates the need for costly and bulky LC filters, thereby lowering EMI emissions and BOM cost.
- The MAX9744 is ideal for MP3 docking stations, gaming consoles, and flat-panel televisions.
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SUNNYVALE, CA—July 21, 2008—Maxim Integrated Products (PINK OTC MARKETS: MXIM) introduces the MAX9744, the industry's first 20W stereo Class D speaker amplifier to operate from a 4.5V to 14V power supply. The wide supply range minimizes the cost of portable designs by reducing component count and allowing the use of a smaller battery pack. The MAX9744 provides ample output power throughout the power-supply voltage range, making it ideal for MP3 docking stations, gaming consoles, and flat-panel televisions.
Additionally, the MAX9744 integrates 64-step analog and digital volume control. In analog mode, the volume range is ratiometric relative to VDD. To ramp up or down the volume digitally, the system microcontroller can program a 6-bit register through the MAX9744's I²C interface.
External feedback resistors set the input gain, while the output has an internally set gain. When powered from a 12V supply, the MAX9744 combines these gains with the wide volume-control range, and delivers 20W per channel into 4Ω speakers.
Class D amplifiers are known for high power efficiency, and the MAX9744 does not disappoint with its 93% efficiency while delivering 20W into an 8Ω load. Achieving high 75dB PSRR, low 0.04% THD+N, and greater than 90dB SNR, this stereo amplifier offers Class AB performance with Class D efficiency.
Due to the switching nature of the output stage, most Class D amplifiers require large, costly output filters; exhibit poor THD+N; and radiate electromagnetic interference (EMI). The MAX9744, however, employs Maxim's patented 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, which eliminates the large LC filters required by traditional Class D amplifiers. These two modulation schemes minimize design cost and space, and they eliminate the time-to-market problems associated with EMI radiation.
The MAX9744 includes a low-power shutdown mode, a mute function, and integrated click-and-pop suppression. Available in a 7mm x 7mm x 0.8mm, 44-pin TQFN package, the device is fully specified over the -40°C to +85°C extended temperature range. An evaluation kit is available to speed design implementation. Pricing starts at $2.45 (1000-up, FOB USA).
Maxim Integrated Products is a publicly traded company that designs, manufactures, and sells over $2 billion of high-performance semiconductor products annually. It was founded over 25 years ago with the mission to deliver innovative analog and mixed-signal engineering solutions that add value to its customers' products. To date, Maxim has developed over 5700 products serving the industrial, communications, consumer, and computing markets. For more information, go to www.maxim-ic.com.
*U.S. Patent #6,847,257.
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