Class D amplifiers:great sound, slim systems!State-of-D-art in digital amplifier performance

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In today’s digital markets, consumers want more fromaudio – multichannel surround sound performanceand slimline ‘designer style’ systems. Fulfilling theseexpectations takes high performance technology andthat’s what Philips Semiconductors’ class D amplifiersdeliver – with innovative solutions that transformsystem design.

At up to 95% efficiency, class D technology marks ahuge advance over traditional AB type devices.By significantly reducing wasted energy, highly advancedclass D amplifiers eliminate the need for heavy, bulkyheatsinks, giving you the key to smaller, lightweightaudio systems.Whatever your application, PhilipsSemiconductors’ class D amplifiers offer small size,

low power consumption and low heat dissipation,simplifying design-in, saving space, cutting costs – anddelivering a fantastic sound experience.

You don’t have to compromize quality, size or priceto offer the latest in end-product design fashions.Our class D amplifiers help you create digital ‘lifestyle’products – including compact speaker sets for fast-growing multichannel DVD / Super Audio CDand home cinema systems. Offering outstanding performance, they ensure an excellent signal-to-noiseratio of over 100dB and low THD levels. Plus with upto 150 W output per channel, you’ll find our leading-edge class D families offer all the power you need.

A new class of audio experience

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In a class of their own for easy designDesigned to give you the competitive edge,Philips’ class D devices set new standards indigital amplifier performance, utilizing Philips’key process technologies and unique designexpertise to maximize the benefits of class D.Most important, we’ve focused on ease of design-in, so you can integrate these devicesquickly to get to market fast. Highly advanced,our class D amplifiers require few externalcomponents and ensure excellent levels of EMC(ElectroMagnetic Compatibility), simplifyingintegration with other system components.What’s more, we support you with comprehensive design support, making your design task even easier.

Dedicated to audioFew companies offer such a wealth ofsound system experience as PhilipsSemiconductors, and we have a longhistory of research and design achieve-ments in audio amplification.We werefirst to enter high volume production ofthin-film SOI (Silicon On Insulator) smartpower technology and first to introducehighly integrated, monolithic, high powerclass D amplifiers.

Our class D amplifiers are part of Philips’rich set of audio technologies, enablingus to deliver total system solutions foraudio applications stretching from sourceto speakers. Whether you need matureanalog or advanced digital devices, ourcomprehensive audio amplifier portfolioensures the right solution. We partneryou with the strength of a companydedicated to technology and widelyrecognized for its industry-leadingexpertise in areas such as RF – know-howincorporated into our class D amplifiersand which helps you develop systems ina highly cost-effective way.

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Ideal for ‘designer style’ consumer applications, PhilipsSemiconductors’ class D amplifiers ensure an unrivalledprice / performance ratio which also makes themperfect for cost-driven markets such as PC speakersand micro systems. And class D delivers the performance you need for ‘demanding’ systems includingautomotive booster and subwoofer applications,which require a wide temperature and / or powerrange. Among many potential applications are:

• DVD-receiver and high-end TVs• mini- and micro-sized audio systems• audio separates• multi-channel speaker sets• PA systems• booster for (sub)woofers• car audio.

Today’s class actPhilips’ latest series of class D products consists ofthe TDA8920 controller IC family and TDA8921 andTDA8922 families of power stages.These highly integrated two-chip amplifier solutions combineexcellent THD (0.01%) with the benefits you’d expectfrom Philips’ state-of-the-art class D design and its exceptionally high efficiency.

By enabling significant power savings, these devicesallow for smaller power supplies and greatly reducethe need for heatsinks, increasing reliability and simplifying design. And superb EMC ensures easysystem integration, minimizing interference effectswith sensitive components such as radio receivers.So overall your applications can be smaller and lighter,with longer battery life in portable products.

Top of the class in your applications

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Operating from a symmetrical supply, the ICs featurean adjustable internal oscillator (200 – 600 kHz) withtracking option for external override. Supportingloads from 4 Ω to 8 Ω, the output stages accept BTLor SE configurations and are protected against shortcircuit and overheating.

Key features of our TDA892x range include:• power ranges from 20 W to 150 W

- up to 400 W with application support• up to 95% efficiency• differential inputs• application support

- EMI, PCB, multi-channel and tuner compatibilityhigh power (300 W) demoboard.

Through unique technological design and application‘tricks’, we’ve lowered class D’s electromagneticinterference (EMI) at high power, as well as reducedpower consumption and improved sound quality –all at a low price. Plus, due to our innovativepackaging solutions and attention to the smallest of

design details, such as pin layout optimization, youcan apply the benefits of class D in a vast range ofproducts.

And when it comes to design-in, Philips’ broad knowledge base and in-depth design support – evenextending to PCB layout for optimized EMC performance – ensures you can obtain the best endresults with our class D amplifiers.

Roadmap to the fully digital futureOur current families will be joined by a series of single-chip class D audio amplifiers: the TDA8920(released),TDA8921 and TDA8922. Capable of delivering up to 150 W output power, they will offersimilar features as our two-chip amplifiers withenhanced performance, together with all the design-in advantages of a true one-chip solution.

As part of our leadership in digital amplifier performance, Philips has developed ‘Zero DeadTime’ technology.This reduces the transition timebetween the transistor’s high (on) and low (off)states to virtually zero, thereby minimizing a keysource of noise in open loop digital amplifiers andgreatly enhancing sound performance (THD).

Power (W) SE/BTL Channel TDA8926 TDA8927 TDA8929

20-50 SE 8 Ω Stereo

50-100 SE 4 Ω Stereo

50-100 BTL 4 Ω Mono

100-150 BTL 4 Ω Mono

150-200 BTL 4 Ω Mono (2pcs)

200-300 BTL 4 Ω Mono (2pcs)

TDA8920 TDA8921 TDA8922

Stereo 2 x 50-100 W 2 x 25-50 W 2 x 15-25 W

Mono 150 W 100 W 50 W

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Philips Semiconductors’ advanced SOI fabricationprocess sets our class D products apart from thecompetition. Featuring very high power output andminimal power dissipation, SOI simplifies design-inand reduces your total system costs.

The low heat dissipation of our class D technologyresults from switching current technology and thelow on-resistance (RDS(on)) of our SOI-based A-BCD1 process. It also gives excellent power handling capabilities, allowing designers to choosebetween lower heat loss or higher current handlingfor the same chip size, or a smaller chip with thesame dissipation.

The advantages of our A-BCD process stem mainlyfrom four inherent SOI characteristics:

• reduced resistance (RDS(on)) for increased reliability, even at high volume with high power

• no latch-up – virtually eliminating adverse effects due to high external voltages, spurious interference or cross-talk via the substrate

• much greater packing densities enabling size reductions up to 30% – a major improvement overbulk silicon

• significantly reduced parasitic capacitance resulting from excellent insulation, enabling quicker and easier design-in

SOI A-BCD handles analog and digital power simultaneously, enabling optimized system solutionswhich combine high-voltage amplifiers and small-featurelogic, together with D/A and A/D converters.

A closer look at class DSimilar in principle to the switched-mode power supply, class D uses pulse width modulation (PWM)techniques because of their superior performancecompared to sigma-delta techniques. By switching theoutput power circuits completely off when there is nosignal to amplify, conduction is stopped and energylosses are minimized. Up to 95% efficiency is attainedfor high power output and typically over 80% atlower power levels (1/8 PoutMax).

At the first stage, Philips’ current class D design compares an analog input signal to a 360 kHz samplingfrequency to generate a rectangular wave output,whose width modulation represents the input signalinformation.A triangular-shaped sampling signal isused and its extremely high frequency – severalorders outside the audio band – ensures the desiredsignal is uncorrupted by the process.The comparator’saccurate signal conversion is ensured through asophisticated regulator producing a very stable reference voltage, and the common-mode rejectionproperty which ensures stable threshold triggeringacross the input’s entire dynamic range.

The resulting digital signal is then fed to a switchingpower amplifier stage, designed and manufactured tovery precise specification. Our TDA8927 IC is able toswitch an incredible 7.5 A peak current at over 300kHz, with negligible rise- and fall-times, ensuring avery clean reproduction of the original signal. Finally, alow pass filter stage removes the carrier frequency aswell as current pulses caused by switching, limitingemissions that could cause EMC problems.

Unique SOI technology for class D:

the inherent audio benefits

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Combined with special protection and shielding circuitry, Philips Semiconductors’ class D amplifier ICsachieve impressive performance specifications, with aflat frequency response between 20 Hz – 20 kHz, andextremely low noise and distortion figures.

The trend towards smaller, digital systems with stunningmultichannel sound and the need for devices toconsume less power make our class D ICs today’sessential solution.With an incredible power per mm2

of silicon, in any audio system class D guaranteesgreat sound.

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MSD758

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www.semiconductors.philips.com

Phil ips SemiconductorsPhilips Semiconductors is a worldwide company with over 100 salesoffices in more than 50 countries. For a complete up-to-date list ofour sales offices please e-mailsales.addresses@www.semiconductors.philips.com.A complete list will be sent to you automatically.You can also visit our websitehttp://www.semiconductors.philips.com/sales.

© Koninklijke Philips Electronics N.V. 2002 SCS 76All rights reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and maybe changed without notice. No liability will be accepted by the publisher for any concequence of its use. Publication thereof does notconvey nor imply any license under patent- or other industrial or intellectual property rights.

date of release: July 2002document order number: 9397 750 10115

Printed in the Netherlands