ADI's new family of Class-D audio amplifiers target advanced TV and automotive applications with best-in-class performance and EMI reduction at power levels up to 2 x 40 Watts.
Analog Devices Inc. introduced a family of audio amplifiers that combine the space- and heat-saving advantages of Class-D amplification with ADI's advanced audio signal processing technology to deliver dramatic improvements in sound quality. Analog Devices' Class-D audio amplifiers outperform competing devices on the key performance requirements of audio fidelity and EMI (electro magnetic interference), previously the most difficult to attain using a Class-D architecture. No other Class-D device has been able to achieve less than 0.005 percent THD+N (total harmonic distortion plus noise) and up to 2 x 40 W output power while reducing heat dissipation by 50 percent in a one-chip solution. This unique combination of features resolves design challenges in consumer applications such as HDTV and home theatre systems, which demand high performance audio from the smallest possible sound systems. EMI reduction prevents interference with other electronic equipment, which is particularly important in the design of automotive audio systems.
The AD199x Class-D amplifiers outperform competing PWM-based (pulse width modulation) Class-D schemes by using a highly-integrated single-chip design which features a "high modulation factor" Sigma-Delta architecture, configured in a closed-loop implementation with a high power output stage. Ultimately, this enables higher audio fidelity in half the space of competing devices and meets the demands of next-generation electronics, such as thin flat panel TVs and multichannel surround sound car stereos.
The AD199x amplifiers deliver audiophile sound quality (THD<0.005 percent; SNR>101dB; PSRR>65dB) with 50 percent lower heat dissipation than traditional linear amplifiers. The devices'breakthrough performance is achieved through Analog Devices' closed-loop, mixed-signal integration of 7th Order Sigma-Delta modulator technology with high-power output drive circuitry and bridge circuitry. Radiated and conducted out-of-band RF emissions are minimized with Analog Devices' advanced modulation techniques and closed-loop, Sigma-Delta architecture to enable a significant reduction in EMI.
The AD199x amplifiers, including the AD1990, AD1992, AD1994 and AD1996, are single-chip devices containing an integrated stereo modulator and stereo “bridge-tied" load (BTL) power stage. Power levels range from Stereo 5 W (Mono 10 W) to Stereo 40 W (Mono 80 W). The AD1994 can be configured in a modulator-only mode. This, coupled with external high power FETs enables very high power amplification, limited only by the power stage design. The parts also incorporate critical peripheral functions, including pop/click suppression circuitry as well as short-circuit, overload and temperature protection.
The AD199x amplifiers can be combined with other Analog Devices audio products, including ADCs (analog-to-digital converters), DACs (digital-to-analog converters) and CODECs, as well as its SigmaDSPВ® and SHARCВ® audio processors.
Availability and Pricing
The AD199x Class-D amplifiers are now sampling, with full production quantities available beginning in April 2005.
| Part No. | Output Power | THD+N | Packaging | 1K Per-Unit Price |
| AD1990 | 2 x 5W | <0.005% | 64-lead LFCSP (lead frame chip scale package) | $2.90 |
| AD1992 | 2 x 10W | <0.005% | 64-lead LFCSP | $3.28 |
| AD1994 | 2 x 25W | <0.005% | 64-lead LFCSP | $4.42 |
| AD1996 | 2 x 40W | <0.005% | 32-lead PSOP (power small outline package) | $6.99 |
