Electronic Design

Dual-Channel SLIC Simplifies Line-Card Designs

The smallest footprint to date for two subscriber-line interfaces (SLICs) makes the Si3220 and Si3225 the most compact solutions for designers building line cards for central-office (CO) systems and PBXs. The Si3220 ProSLIC targets shorter-loop (2000 to 12,000 ft.) customer-premise equipment, while the Si3225 is optimized for CO and other long-loop (up to 18,000 ft.) applications.

With either of these SLICs, designers can implement a dual-channel line card in an area of just 1.95 in.2 with only 41 components. Alternative solutions could require almost double the area and double the number of components.

Included on the dual ProSLIC chips is a comprehensive set of signal-generation, line monitoring, and diagnostic processing tools to detect subscriber line faults and equipment malfunctions. The integrated tool set allows carriers as well as independent service providers to remotely diagnose subscriber loop faults and line-card equipment failures without requiring centralized test equipment or service tech- nician involvement.

Both chips also integrate all SLIC and codec functions, including all the BORSCHT functions, into one low-voltage, low-power CMOS chip. The Si3220 includes an internal ring generator, eliminating the need for an external ring generator and ring relays. Alternately, the Si3225 provides full compatibility with existing access infrastructures that employ a centralized ringing architecture.

The chips are designed to work in conjunction with the company's Si3200 line-feed interface chip, which integrates the high-voltage (100-V) circuitry necessary for the Si3220 and 3225 to control and monitor the telephone line. The two-chip combination (Si3220 and Si3200, or Si3225 and Si3200) provides a globally compliant solution that can be software-configured for all dc feed and audio transmission parameters, ringing, DTMF generation and decoding, caller ID generation, and loop supervision criteria such as loop closure, ring trip, and ground key detection.

The Si3220 and 3225 are housed in 64-lead TQFPs. The companion Si3200 comes in a 16-lead SOIC package. Per-channel price for the chip set (half of a 3220 or 3225 and one Si3200) starts at $5.14 in 10,000-unit quantities. Samples are immediately available, with production quantities available in the first quarter of 2002. Evaluation boards for the Si3220 or Si3225 are available for $150.

Silicon Laboratories Inc., 4635 Boston Lane, Austin, TX 78735; Dave Bresemann, (512) 416-8500; www.silabs.com.

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