ADI Introduces Class D Audio Amplifier

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Analog Devices Inc. (ADI) has introduced two Class D audio amplifiers to meet the low power consumption, small size and ever-increasing high-fidelity design requirements of portable electronic devices. ADI's leading provider of innovative audio processing solutions for home and professional applications, with the expertise of its Class D amplifiers, meets the small size and battery-powered low power consumption of mobile phones, portable game consoles, MP3 players, notebook computers and handheld media devices. Demand.

ADI's SSM2301 and SSM2304 Class D amplifiers are designed to effectively drive speakers in handheld or portable consumer applications by minimizing power consumption, using sigma-delta modulation to reduce electromagnetic interference (EMI) and using an integrated filterless structure No external components are required.

"Combining the low power and small package advantages of Analog Devices' Class D audio technology with its linear IC expertise, it offers a wide range of high fidelity sound applications, from mobile phones and MP3 players to portable devices and ultra-thin tablets. "Advanced TV and multi-channel surround sound car audio," said Steve Sockolov, director of precision signal processing product line at Analog Devices. "Although most Class D amplifiers use some kind of pulse width modulation (PWM) conversion, Analog Devices' Class D amplifiers. Σ-Δ pulse density modulation (PDM) is used to reduce the amplitude of the high frequency spectral components, thereby minimizing the effects of EMI."

The SSM2301 (mono) and SSM2304 (stereo) amplifiers operate up to 85% efficiency over a wide range of output power ranges. The SSM2301 delivers 1.4 W of output power from an 8 ohm (Ω) load; the SSM2304 provides 2 W of output power from a 4 Ω load. Both amplifiers operate from a single 2.5 V to 5.5 V supply with a 20 nA standby current maximum micropower standby mode with built-in thermal standby and output short-circuit protection. Both amplifiers operate at low voltages, making them suitable for applications such as cell phones, which use battery power to directly drive speaker amplifiers.

The new Class D audio amplifier is available in an ultra-small 8-pin, 3 mm × 3 mm LFCSP package. The use of a filterless circuit structure eliminates the need for an external output filter, further saving printed circuit board (PCB) area.

The SSM2301 and SSM2304 drive their maximum output load with a 5 V supply voltage with harmonic distortion plus noise (THD+N) of less than 1% and a signal-to-noise ratio (SNR) greater than 98 dB. The fully differential input feature provides excellent rejection of common mode noise at the input. The amplifiers also include a snubber-suppressing circuit that reduces both enabled and un-activated noise while providing a flexible, fixed or user-adjustable gain configuration.

The SSM2301 and SSM2304 amplifiers are new additions to the latest addition to Analog Devices' Class D amplifier family, which also includes the AD199x family of audio power amplifiers.

Samples of the SSM2301 and SSM2304 Class D audio amplifiers are available now, and high-volume products will be available in August 2006, priced at $0.55 per unit in 1,000-piece quantities. The product operates over the industrial temperature range of -40 ° C to +85 ° C. An evaluation board with a measurement filter is also available.