VSC7157

Enhanced 36-PHY 1.5Gbps and 3.0Gbps SAS

Edge/Fanout Expander

Low-Cost Single-Chip SAS Edge/Fanout Expander with Comprehensive

Statistics (per PHY)

All versions are being discontinued and are subject to Last Time Buy, after which new

orders can not be placed.

Description

The VSC7157 is a 36-PHY Serial Attached SCSI (SAS) edge/fanout expander. The device

provides SAS port expansion as defined by the ANSI T10 Serial Attached SCSI 1.0 and 1.1

specifications for both edge and fanout expanders. The VSC7157 is targeted at embedded

applications in the midrange and enterprise storage environments including blade servers,

JBODs, and RAID systems. It offers an attractive technology upgrade for those systems that

currently employ parallel SCSI technology and have substantial reliance on SCSI-centric

applications software or management solutions.

The VSC7157 provides active port expansion for up to 36 connected PHYs with connections

made via a high-performance internal nonblocking cross-bar matrix.

Programmable output preemphasis and input signal equalization ensure consistent high signal

quality in lengthy in-and-out-of-box backplanes or cable infrastructures.

The on-board CPU in the VSC7157 performs the role of an SMP management application client

and can participate in enclosure management functions through serial I²C interfaces, an

embedded Ethernet controller, or vendor-specific SMP implementations.

The VSC7157 is a SAS expander containing all the functions needed to implement a 1.5Gbps

or 3.0Gbps SAS enterprise server or JBOD system. This device is typically used in distributing

SAS signals to an array of disk drives either in a server or an external enclosure. Commonly,

two or more “initiator” ports connect to the SAS SAN and several disk ports connect to drives

over a 3Gbps serial backplane. The embedded enclosure management controller,

software/firmware-compatible with other Maxim enclosure management controllers, configures

and monitors both the VSC7157 and the entire enclosure through flexible low-speed interfaces.