SAS Expanders Enhance Enclosure Design

Designed for enterprise server and enclosure applications, the VSC7156 24-PHY, VSC7157 36-PHY, and VSC7158 18-PHY Serial Attached SCSI (SAS) expanders provide enhanced capabilities including standard PHY and address-resolved zoning, a multi-affiliation STP/SATA bridge, and Ethernet MACs. Bridging the gap between the SAS 1.1 and emerging SAS 2.0 specifications, the devices’ PHY and address-resolved zoning meet the T10 working group of INCTS under accreditation of ANSI requirements. The devices embed a 32-bit RISC CPU, which delivers enclosure management (EM) functions directly onto the expander, while two adjunct processing engines in the EM subsystem support custom SSP and STP initiator and target functions. The entire family of expanders revolves around a common software and hardware architecture, allowing users to scale designs across port densities, functional requirements, and applications while leveraging existing software and firmware. Depending on the device, prices range between $31 and $63 each in volume. VITESSE SEMICONDUCTOR CORP., Camarillo, CA. (800) 848-3773.