Digital Power Amps Enhance Auto Audio

The second-generation FDA801 and FDA801B power amplifiers promise to simplify design for car-radio system suppliers and deliver better listening experiences to drivers and passengers, even in smaller cars. The devices are four-channel class-D amplifiers with digital inputs that provide immunity to GSM noise, improve sound quality, saves component costs, and simplify system design. Features include a unique real-time measurement of speaker impedance via a Digital Impedance Meter in the FDA801B. Also, an advanced fabrication process, BCD9s, minimizes interference between circuits on the chips, lowers standby-power consumption, and cuts power-transistor dissipation, thereby raising efficiency to more than 93%. The FDA801 and FDA801B are available immediately in LQFP64 Exposed Pad Up packages.

Specs include:

• 115dB Signal to Noise Ratio (SNR); 110dB dynamic range
• Simplified digital input eliminates external DAC (Digital to Analog Converter) and external decoupling capacitor, thereby avoiding potential DC-offset problems
• More than 40% power saving compared to standard class-D amplifiers
• Digital Impedance Meter (DIM, in FDA801B) automatically recognizes magnitude and phase of the connected speaker and communicates it by digital bus (I2C)
• Internal 24-bit DAC conversion and very low noise in line-driver and amplifier modes ensure superior audio performance
• On-demand advanced diagnostics allows each channel to independently perform AC or DC diagnostics with configurable parameters
• Ability to drive loads down to 1 ohm gives designers complete flexibility to specify preferred speakers

Datasheets for the FDA801 and FDA801Bv, respectively, are available at:
http://www.st.com/st-web-ui/static/active/en/resource/technical/document/data_brief/DM00246294.pdf
http://www.st.com/st-web-ui/static/active/en/resource/technical/document/data_brief/DM00246298.pdf

STMicroelectronics
Burlington, MA
781-861-2650
http://www.st.com

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