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STMicroelectronics First in Production with Enhanced Audio for Start/Stop and Hybrid Cars

New generation of audio amplifiers maintains hi-fi sound during engine turn-off and cranking

As car makers introduce features such as engine start/stop to reduce fuel consumption and carbon emissions, STMicroelectronics, a world leader in automotive ICs, is pioneering a new generation of chips that allow in-car entertainment equipment to operate without interruption as the engine is turned off and restarted. The first of these is the TDA7850LV, a 4x50W audio power amplifier that is the very first start/stop-compatible IC of its kind in production.

Some manufacturers estimate that start/stop and other technologies such as high-efficiency engine management programs could be a big contributor to reducing energy usage, cutting fuel consumption by as much as 20% in certain models over the coming years. The system shuts down the engine when the vehicle is stopped, for example at traffic lights, and restarts as the driver prepares to move off. According to market analyst Strategy Analytics, annual demand for vehicles featuring start/stop is expected to reach almost 20 million units by 2015, initially led by customer demand in Europe.

In cars fitted with start/stop, the supply voltage for on-board electrical equipment can fall to as low as 6V when the engine is turned off and restarted and only the battery is supplying electrical power. In addition, switching between battery power and alternator power can generate ‘pop and click’ noise. Left unaddressed, these effects can cause noticeable distortion in the audio system’s output. Hybrid-electric vehicles present similar challenges to electronic equipment designers.

Discrete components external to the audio power amplifier can be used to build circuitry to regulate the supply voltage and suppress pop and click noises. However, these circuits complicate design and add significantly to bill-of-materials costs. ST’s TDA7850LV audio power amplifier makes the use of all these components unnecessary and therefore simplifies design, reduces cost, and saves pc-board space.

ST is building a complete family of start/stop audio power amplifiers that will include entry-level class-AB amplifiers, complex digital devices with diagnostic features, and an automotive class-D family offering outstanding power efficiency.

“This emerging family of devices, beginning with the TDA7850LV, combines advanced start/stop capability with the hi-fi audio quality and outstanding ruggedness that have always distinguished ST’s audio power ICs and ensured our strong market leadership,” said Fabio Marchio, Automotive Product Group Vice-President and General Manager of ST’s Automotive Infotainment Division. “We call this new wave of products ‘green power,’ meaning that we are totally committed to design ICs that can help our customers implement environment-friendly systems. We now aim to build on our leadership as demands for start/stop and hybrid technologies continue to ramp up.”

In addition to its start/stop compatibility and high audio performance, the TDA7850LV delivers the advantages of ST’s Flexiwatt power package, now the de-facto standard for car audio ICs. A variety of configurations are available, including vertically or horizontally mounted packages. In addition, a unique new surface-mount variant now allows car-audio makers to take advantage of high-speed fully automated assembly enabling increased throughput and production quality.

Major features of the TDA7850LV:

— 4x50W MOSFET output stage
— 2 Ohm output driver compatible with diverse speaker types
— Hi-fi class distortion and low output noise, yielding high sound quality
— Integrated 0.35A high-side driver supporting functions such as antenna
— Protection against common vehicle electrical hazards:
— Short circuits to ground and battery
— Open-circuited speakers
— Highly inductive loads
— Load-dump
— Over-temperature

The TDA7850LV is currently ramping-up mass production, priced at $5.30 for orders of 1000 pieces. Alternative pricing options are available for larger volumes.

About STMicroelectronics

STMicroelectronics is a global leader serving customers across the spectrum of electronics applications with innovative semiconductor solutions. ST aims to be the undisputed leader in multimedia convergence and power applications leveraging its vast array of technologies, design expertise and combination of intellectual property portfolio, strategic partnerships and manufacturing strength. In 2009, the Company’s net revenues were $8.51 billion. Further information on ST can be found at

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