Electronic Design

Repeater Chip Opens Up InfiniBand Design

Sometimes it's the small things that count, especially in networking. For example, in switch fabrics, implementations may need more than just the standard nodes—HCAs, TCAs, and switches. One key part is a repeater, a chip that strengthens and passes on InfiniBand signals. Primarion fields an InfiniBand repeater that enables designers to extend their signal reach both on the board, within the box, and for linking systems.

The PX5120 Retiming and Repeater chip supports a single 2.5-Gbit/s InfiniBand channel. It delivers a "skip-free" architecture that doesn't consume a packet "skip-bit" in passing through the chip. It consequently has no packet overhead, allowing the packet to keep its two skip-bits for future consumption. No skip-bits are added or deleted in the passage through the repeater.

Chip latency is 30 packet bits (120 ns at a 250-MHz clock). The chip provides independent clock and data recovery for each receive channel. It supports a 125- or 250-MHz differential or single-ended selectable reference clock.

The chip recovers the received clock and data and reregisters the serial data using a PLL-generated reference clock. The data is retransmitted at the received rate. The data rate is unchanged, regardless of how many repeater stages are used in a link path. For diagnostics and test, the chip has a built-in local loop-back path and a JTAG port.

The 2.5-V chip comes in a 196-BGA package. Typical power dissipation is 1.6 W (full duplex). The chips cost $30 each in 1000-unit lots.

Primarion, 2507 W. Geneva Dr., Tempe, AZ 85282; (602) 454-7220; fax (602) 659-4617; www.primarion.com.

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