VSC7157XYS-03

The VSC7157XYS-03 is an enhanced 36-PHY Serial Attached SCSI (SAS) edge/fanout expander from Analog Devices, operating at 1.5Gbps and 3.0Gbps. This single-chip solution provides SAS port expansion according to ANSI T10 specifications, suitable for both edge and fanout configurations.

Targeted at embedded applications within midrange and enterprise storage systems, including blade servers, JBODs, and RAID systems, the VSC7157XYS-03 offers an upgrade path from parallel SCSI technology. It features a high-performance internal nonblocking cross-bar matrix for active port expansion up to 36 PHYs. Programmable output preemphasis and input signal equalization ensure signal integrity across backplanes and cable infrastructures.

The device integrates an on-board CPU for SMP management functions, supporting enclosure management via serial I²C interfaces, an embedded Ethernet controller, or vendor-specific SMP implementations. It contains 36 10-bit serializer/deserializers (SerDes), per-PHY diagnostics, retiming elasticity buffers, and a target/initiator-capable SMP virtual PHY engine. Error detection includes 8b/10b violations, data path parity errors, disparity errors, and CRC errors.

This SAS expander is typically used to distribute SAS signals to disk drive arrays in servers or external enclosures. It is compatible with existing Maxim enclosure management controllers, allowing for software reuse and reduced time-to-market. The VSC7157XYS-03 is a highly integrated solution offering high-performance characteristics and industry-leading high-speed I/O capabilities.