1998-12-02 , E/IC-1041/54
Product News From Philips Semiconductors

New process technology enables power efficiencies of typically 95% to be achieved

Philips Semiconductors, the largest European semiconductor company, has used its new SOI-based A-BCD1 process technology to create a new family of single chip, Class D, digital audio power amplifiers with much greater efficiencies than current designs. The TDA8920 is the first single chip amplifier that can handle 2 x 50W. The efficiency of typically 95%, compared with the typical 50% for Class AB amplifiers, means that much less power is wasted, reducing or removing the need for heat sinks, shrinking power supplies, and significantly increasing the battery life of portable audio products.

The key to the reduced power wastage is that the A-BCD1 transistors have very low resistances (R_ds(on)) when on, due to the SOI technology. (See accompanying backgrounder on the A-BCD1 technology) The isolation of the components by the oxide layer improves the audio quality by removing problems with parasitic capacitances and latch-up, making the design of these amplifiers much easier and quicker. The robustness of the process technology also protects them from voltage spikes and fault conditions that can occur in automotive car radio applications.

As so little waste heat is produced by these new amplifiers, they open up a range of new uses, such as directly fixing onto the Printed Circuit Board (PCB) of a TV or computer as the 2 x 10W version does not require a heat sink. Another use where the amplifiers' small size and low power consumption are ideal is for digital speakers.

In the past, Class D amplifiers required discrete power transistors as well as a separate CMOS IC to provide the intelligence. Philips Semiconductors' A-BCD1 process combines Bipolar, CMOS and DMOS on a single IC so that these products, which can handle analog and digital power simultaneously, can be made at very competitive prices. The range comprises the 2 x 50W TDA8920, which will be available this month. This will be followed in a few months by the 2 x 10W and 2 x 25W amplifiers and later by versions going up to single chip solutions for handling 2 x 100W.

Philips Semiconductors, a division of Royal Philips Electronics, headquartered in Eindhoven, The Netherlands, is the ninth largest semiconductor supplier in the world and the third largest supplier of discretes in the world. Philips Semiconductors' innovations in digital audio, video, and mobile technology position the company as a leader in the consumer, multimedia and wireless communications markets. Sales offices are located in all major markets around the world and are supported by systems labs.

For more information, see also:
BG9809: Philips Semiconductors' BCD technology on Silicon On Insulator process offers greater power handling, improved robustness and easier design.