VSC7130 データシートの表示（PDF） - Vitesse Semiconductor

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VSC7130

Dual Repeater/Retimer for Fibre Channel and Gigabit Ethernet

Vitesse Semiconductor 

VITESSE

SEMICONDUCTOR CORPORATION

Dual Repeater/Retimer

for Fibre Channel and Gigabit Ethernet

Data Sheet

VSC7130

Applications

Several Fibre Channel and Gigabit Ethernet applications can use the VSC7130. Configuration changes

between different applications are accomplished with mode pins and the Two-Wire Interface. SI+/- and SO+/-

are normally connected to the duplex interface from the system while TX+/- and RX0+/- or RX1+/- are con-

nected to the external link through a connector or optical transceiver. Redundant receive inputs are provided in

order to optimize layouts with copper connectors or optical modules. CDR0 improves the signal quality of SI

and retransmits the data on TX. CDR1 improves signal quality of RX0 or RX1 and retransmits recovered data

to SO.

In this document, the term “Repeater” will be used for a clock and data recovery function (CDR) where the

recovered serial data is retransmitted synchronously to the recovered clock. Unlike standard PLL-based CDRs,

this circuit is all-digital which results in good jitter tolerance, excellent jitter transfer and low latency in a circuit

which performs identically across process, voltage and temperature.

The term “Retimer” is used for a CDR which retransmits the recovered serial data synchronously to the

local reference clock. This complex CDR function eliminates jitter transfer at the expense of latency. Due to the

potential mismatch between the baud rate of the incoming data and the local reference clock (i.e. +/-100ppm),

an add/drop elasticity buffer is needed to insert/delete Ordered Sets to match this rate difference. The data

which is added/dropped must meet Fibre Channel protocol specifications. By eliminating jitter transfer, stan-

dards compliance is ensured. The retimer function is not available for Gigabit Ethernet.

Multi-Node Switch

One application for the VSC7130 is in high port-count Fibre Channel and Gigabit Ethernet systems such as

switches. Figure 1 shows a switch with a CMOS protocol ASIC with integrated Serializer/Deserializers located

on the Switch Fabric card. Serial data from the protocol ASIC passes through multiple connectors and long

traces on the PCB before reaching the connector. Without the VSC7130, the signal quality at the connectors

would result in poor system performance. However, by using the VSC7130, signal quality is improved to meet

the specifications of Fibre Channel and Gigabit Ethernet at the system interface connectors.

Figure 1: Fibre Channel or Gigabit Ethernet Switch

Port 1

Port N

Protocol ASIC

Switch Fabric Card

Backplane

Connectors

VSC7130

CDR0>

<CDR1

Line Card

Page 2

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com

Internet: www.vitesse.com

G52297-0, Rev 4.0

04/02/01

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