Transceiver, codec debut by Crystal Semiconductor

Electronic News, Feb 13, 1995

AUSTIN, Texas--Cirrus Logic subsidiary Crystal Semiconductor unveiled a multiple-standard infrared (IR) transceiver allowing data transfers between equipment from different manufacturers. Separately the Cirrus unit also launched two coder/decoders coders) for audio systems and radio modules.

The CS8130 IR transceiver chip implements the new Infrared Data Association (IrDA) standard providing cordless communication capabilities for mobile computers and peripheral devices. The device, for example, provides a vehicle for exchanging data between personal digital assistants or other portable computers to a desktop PC as well printers and fax machines for producing hard copies of files.

In addition to the IrDA standard, the CS8130 also supports the 500Khz ASK and 38Khz ASK TV remote mode specifications and direct mode no modulation or decoding) operations. Some foreseeable applications include use with Sharp's Wizard PDA and TV channel selection on a PC via traditional TV IR remote control devices. The CS8130 also provides the hardware needed to give PDAs the capability to controlling TV programming and to download instructions to VCRs, Crystal said.

"IR technology has a vital role to play in the wireless communications revolution," said Wayne Alvarez, Crystal's marketing manager for personal communications products. "The previous lack of standards was a major obstacle to the proliferation of infrared technology in computer equipment, and its interoperability the broad of consumer products."

The CS8130 connects to a standard UART via TXD, RxD and two handshake pins, and data transfers range from 2,400bps to 115.2Kbps in half- or full-duplex mode. A standard LED and PIN diode attach directly to the device while a baud clock generator and programmable registers allow the various options to be set. Available in a 20-pin SSOP, the CS8130 is priced at $5.50 in 1,000-unit quantities. Production quantities, an evaluation kit (CDB8130), software and documentation are available now.

Crystal also expanded its product portfolio with the new codecs. The CS4225 multi-channel audio codec is geared to replace discrete components in high-performance consumer sound systems, said Al Shuele, Crystal's VP and GM of the Industrial Products Division. For example, in a typical automotive audio system, one codec replaces three stereo data converters, three volume control ICs, one input multiplexer, a 12-bit analog-to-digital converter (ADC) and discrete analog filtering components. Existing solutions, which typically require 10 square-inches of board space, can be accomplished with the CS4225 in one-square-inch, significantly reducing design complexity, lowering costs and dramatically increasing system reliability."

The CS4225 contains an on-board Phase Locked Loop (PLL) used to generate high frequency clocks on-chip from a low-frequency external clock source, which is said to reduce the electro-magnetic interference (EMI) that plagues automotive applications. The chip also supports CD quality audio by incorporating 16-bit ADCs and quad 16-bit DACs. Other features include independent volume control for each output channel, data error signal conditioning, deemphasis and an auxiliary 12-bit ADC.

The device, priced at $22.95 in 1,000-piece quantities, is packaged in a 44-pin PLCC for both commercial and industrial temperature ranges. Samples are available now while volume production is slated for later in 1Q95.

Crystal's second codec offering, the CS6450, bridges 3-volt digital signal processors (DSPs) to 5V radio modules, a feature which reduces power consumption in cellular and other wireless portable communications applications. The codec is designed for cellular phones utilizing such standards as Cellular Digital Packet Data (CDPD), Advanced Mobile Phone Service (AMPS) and Time Division Multiple Access (TDMA) systems.

The radio codec includes several design techniques implemented to minimize internal cross-talk and out-of-channel noise and simplify the external filter design. Interfacing to the digital subsystem via a parallel port, the CS6450 converts between the digital data from the DSP and the analog data format of the radio module. The codec incorporates 1-bit delta-sigma DACs and ADCs for processing in-phase (1) and quadrature (Q) signals and includes three low-speed, 8-bit D/A converters used to control the analog blocks of the radio module. On the analog side, the device interfaces to the radio subsystem and provides signal conversion functions and filtering. Available in sample and production quantities, the CS6450 is priced at $12.20 in 1,000-unit quantities and is housed in a 44-pin plastic TQFP.