STMicroelectronics Announces Compact Audio Power Amplifier Solution for Mobile Phones
STMicroelectronics Inc. has introduced a compact stereo headphone and loudspeaker driver chip, with a flexible I2C bus control interface, which is intended for mobile phones, PDAs and laptop computers. The new TS4956, in a lead-free 2.5x2.4mm flip-chip package, can drive up to 38mW per channel continuous average power into 16Ω headphone loads, or 450mW into 8Ω loudspeaker loads, when operating on a 3.3V power supply.
Mobile phone designers are moving away from traditional audio power amplifiers to more complex integrated audio solutions, and the TS4956 provides such a system by offering three dedicated outputs in a single chip: one stereo headphone drive, one stereo loudspeaker output and one mono line for a hands-free set.
Designed for space-critical applications, the new device minimizes the number of external components required by providing I2C selection of eight different operating modes, including a stereo loudspeaker option, and 32-step -34 to +12dB digital volume control. It features an ultra-low standby current of 0.5mA, with just 10nA shutdown current, and can operate on power supplies from 2.7 to 5.5V. Pop and click noise-reduction circuitry eliminates turn-on and turn-off noise.
The headphone outputs are power limited, by monitoring the output voltage and current in the phantom ground configuration, to minimise the chance of users' hearing damage. In addition, the device itself is protected by an over-temperature shutdown mechanism activated at 150°C. Operating temperature range is -40 to +85°C.
The TS4956 is available now in an 18-bump flip-chip package, priced at $1.10 in quantities of 1,000 pieces.
