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High-performance DACs support six-, eight-audio channels

Posted: 03 Nov 2004 ?? ?Print Version ?Bookmark and Share

Keywords:audio converter ic? cirrus logic? digital-to-analog converter? dac? cs4365?

The CS8421
Expanding its high-performance analog and mixed-signal audio converter ICs, Cirrus Logic Inc. unveiled two new 24bit, 192kHz, multi-channel digital-to-analog converter (D/A converter) ICs, the CS4365 and CS4385.

These high-performance, pin-compatible audio converters offer support for six and eight audio channels, giving system designers premium converters for high-end multi-channel audio applications such as sound cards, super audio CD (SACD) and DVD-audio players, home theater systems, digital mixing consoles, multi-track digital recorders, effects processors and automotive audio systems.

The CS4365/85 converters are improved versions of the company's first generation multi-channel DACs (CS4362/82). Improved overall low-noise performance is made possible by an advanced multi-bit delta-sigma architecture with integrated mismatch noise shaping technology, resulting in dynamic range and THD+N specifications of 114dB and -100dB, respectively. Additional new features include a time-division multiplexed data (TDM) serial interface and a proprietary direct stream digital (DSD) processor for SACD applications, allowing for volume control and on-chip 50kHz filtering without an intermediate decimation filter stage.

The highly integrated CS4365/85 converter family is designed to reduce costs for audio system manufacturers by minimizing the external electrical components required and saving valuable board space. On-chip level shifters for direct interface to logic levels from 1.8V to 5V, patented automatic mode selection based on sample rate detection, selectable low latency digital filters and pin-compatibility all contribute to making these high-end DACs a user-friendly design choice for cutting-edge audio products.

The company also announced a high-performance asynchronous sample-rate convertergiving audio system designers a high-performance, cost-effective silicon solution for synchronizing multiple audio sources.

The CS8421 provides high dynamic range and distortion performance at a fraction of the price compared to competing solutions. This combination of price and performance removes the sample-rate conversion challenges that system designers often encounter and eliminates the need for the conversion process to be completed by DSPs or other ICsthus simplifying and shortening development cycles.

"The key benefit of the CS8421 is that the sample-rate conversion process is transparent," said Carl Alberty, manager of mixed-signal products, Cirrus Logic. "And because the CS8421 eliminates the need for DSPs to use valuable processing power for sample-rate conversion, product designers can focus on solving other system challenges."

The CS8421, a follow-up to Cirrus Logic's CS8420 converter, gives systems designers a cost-effective 32bit, high-performance stereo asynchronous sample-rate converter designed to convert an audio source from one sample rate into another. Digital audio is processed at different sample rates, typically as low as 32kHz to as high as 192kHz.

The CS8421 supports 16- to 32bit resolution and provides a 1:8 /7.75:1 upsample/downsample ratio for sample rates ranging from 8kHz to 211kHz. Low-latency digital filtering, 175dB dynamic range and -140dB THD+N make the CS8421 an ideal solution for a variety of digital audio products, such as automotive audio systems, computer sound cards, DVD recorders, digital mixing consoles, multi-track digital recorders, effects processors and broadcast audio equipment.

The CS8421 also supports a TDM mode, which allows several CS8421 ICs to be serially connected together allowing their output data to be multiplexed onto one line for input into a DSP or other TDM-capable multichannel devices. When operating in this mode, the output data for each device is phase matched. Also included is a bypass mode that allows the input clock and data to be passed directly to the output port without sample-rate conversion.

The CS8421 operates from a 2.5V digital power supply and can interface directly to 3.3V or 5V logic levels. Simple hardware configuration eliminates the need for an external microcontroller, allowing designers to easily implement sample-rate conversion in their product designs.

The CS4365 and CS4385 are available in 48-lead, LQFP packages with lead-free assembly and are priced at $4.29 and $5.48, respectively, in quantities of 10,000. Meanwhile, the CS8421 is available in a 20-pin TSSOP or QFN package and is priced at $4.85, also in quantities of 10,000.

- Bettyann Liotta


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