Crosspoint Switches Reduce Jitter

The VSC8xx crosspoint switch family expands with the introduction of 36 x 36 and 68 x 68 switches. The new parts have integrated signal equalization (ISE) capability to eliminate the effects of inter-symbol interference (ISI) that can occur in applications using long, narrow PCB traces to route the incoming signal, such as Clos switch fabrics in digital cross-connect systems. Described as the lowest in power on the market, the devices incorporate the ISE proprietary functionality on every input to the switching matrix. This Òjitter eatingÓ results in less output jitter when the incoming jitter is deterministic in nature. By reducing jitter, ISE allows the development of large three- or five-stage Clos switch fabrics, improving the multi-pass performance of the switch and eliminating the need for inner stage re-timers. In addition to reducing overall cost in this way, the VSC837 and VSC838 employ input signal activity monitoring for in-system diagnostics. Both switch matrices offer fully non-blocking operations with broadcast and multicast capabilities. The VSC837 68 x 68, which is a 3.2 Gb/s crosspoint switch, and the VSC838, which is a 36 x 36 3.2 Gb/s crosspoint switch, suit designers of high speed applications, such as SONET/SDH dense wavelength division multiplexing, SAN switches and automatic test equipment. Both the VSC837 and VSC838 provide low power dissipation-6W and 11W, respectively. Pricing for the VSC837 is $769 each/1,000 and for the VSC838 is $325 each/1,000.