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Class D amps tout true fidelity

Posted: 13 Jan 2006 ?? ?Print Version ?Bookmark and Share

Keywords:Bettyann Liotta? JAM Technologies? digital TV? True Fidelity? digital-input stereo amplifier?

JAM Technologies Inc. is setting its sights on digital TVs with its latest True Fidelity digital-input stereo amplifiers.

Both of JAM's Class D amplifiers can directly decode a digital audio stream without intermediate digital-to-analog (D/A) conversions, said JAM CTO Larry Kirn. "This maintains the best noise rejection and audio performance possible," he said.

The JM2020 amplifier is capable of providing up to 20W of average power into a 4-ohm load. Short-circuit and thermal-overload protections prevent the part from being damaged during a fault condition. The amp offers roughly 80 percent efficiency, an I2C control bus, a 12V to 16V unregulated analog power supply, and discrete or register volume control. "It provides the efficiency of Class D with audio performance that meets or exceeds conventional Class A/B designs," Kirn said.

The JM2007 Class D amplifier, capable of delivering 7W in a 4-ohm load, is said to feature better than 90dB dc linearity, roughly 90 percent efficiency, and a 7V to 10V power supply. Integrated thermal-overload protections prevent the part from being damaged during a fault condition. With a 0 to 70C operating range, the JM2007 amplifier does not require heat sinking.

The Class D amplifiers both support multiple audio sample rates and feature a -100dB noise floor.

"Today the TV industry is under pressure to deliver CD-quality sound. Other Class D amplifiers can improve efficiency, but at higher cost, greater complexity and lower audio quality," Kirn said.

In addition to flat panel TVs, the devices can be used on compact audio, portable speaker, boom boxes and other audio applications.

JAM's amplifiers are based on a true, digital-input open-loop Class D amplifier design that delivers full 16 bit analog-quality audio with Class D efficiency. The design incorporates a patented Synchronous Bi-modulation technique. This and other new proprietary technologies developed by the JAM's engineering team drive the output stage without creating the errors typical of conventional Class D amplifiers, Kirn said. "Only True Fidelity amplifiers can provide full CD-quality 16-bit resolution at the output," he said.

Both devices come in a 48-pin TAPP (9-by-9mm) package. The JM2020 (20W) is priced at $2.45 per unit in 10,000-piece quantities. Pricing for the JM2007 (7W) is $1.90 per unit in same quantities.

- Bettyann Liotta

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