AUSTIN, Texas " Cirrus Logic Inc. entered the market for Class D digital amplifier controllers on Monday (July 12), aiming at the high-end of the audio-video recorder market as well as recordable DVD players with built-in amplifiers and captive speakers.
Cirrus joins a growing market for digital amplifier chips, with Apogee Technology, D2Audio, Texas Instruments and Tripath Technology among the market participants.
Cirrus, based here, developed two multichannel Class D controllers, one aimed at six-channel receivers and another at eight-channel systems. The devices offer more than 100 dB of dynamic range, which marketing manager Sanjan Voleti said comes in part from noise compensation capabilities on chip. Thus far, Cirrus has offered two-channel amplifier devices aimed at the market for headphone-based portable systems, optimized for 1.8-V operation.
Using pulse width modulation (PWM) techniques, the devices can more easily compensate for clock jitter. "Every manufacturer is tweaking the power supply so the rails don't move around. With PWM, they get better sensitivity for handling jitter with a better sample rate," he said.
Digital amplifiers save considerable amounts of power, and support efforts to deliver low system costs as well. The Cirrus devices, which are sampling now, are priced in the mid-$3 range in volume quantities. However, Voleti said designing with digital amplifiers has been difficult for the system designers working with less expensive power supplies. "We set out to offer solutions that would ease the process of getting into production, so that the system engineers do not have to continually come back to the chip vendor," he said.
The Cirrus devices, called the CS4460 and the CS44800, work with most power supplies in the 20 to 100 Watt range. A reference design and demonstration board supports sample rate converters "that eliminate headaches the system designers can have with a clock that is not as clean as they might like," he said.