VITESSE

SEMICONDUCTOR CORPORATION

Data Sheet

VSC7140

1.0625 Gb/s Fibre Channel

Dual Repeater / Hub Node

G52180-0, Rev 4.0

Page 3

10/23/00

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

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

Internet: www.vitesse.com

Application Examples

The VSC7140 is intended for two applications, Dual Repeater or Dual Hub, as configured by HUB. Users

needing to retime both incoming and outgoing signals at the bulkhead of a Fibre Channel system would use the

part in Dual Repeater Mode (HUB is LOW). Users building Fibre Channel Hubs would use the part in Dual

Hub mode (HUB is HIGH) to fully handle the functions of two Hub Nodes.

Dual Repeater Mode

In this example, the VSC7140 forms a dual repeater in a complex Fibre Channel system, such as a JBOD

(Just a Bunch Of Disks) RAID (Redundant Array of Independent Disks) subsystem, which requires the incom-

ing Fibre Channel signal to be retimed to ensure adequate signal quality to the input of the subsystem. Like-

wise, the output of the JBOD subsystem requires retiming to ensure that the outgoing signal from the system

meets the amplitude and jitter requirements of Fibre Channel. For this application, the dual CRUs are the only

circuits required although the SDUs may be used for reporting signal status. Therefore, the VSC7140 would be

configured as follows:

HUB is LOW to select Dual Repeater Mode.

RX1 connects to the external input from the bulkhead.

SO1 connects to the input to the JBOD subsystem.

RX2 connects to the output of the JBOD subsystem.

SO2 connects to the output to the bulkhead.

TX1 and TX2 are not used. Leave unconnected.

SEL1 and SEL2 are driven HIGH.

FAIL1- and FAIL2- may be used for status. ERRSEL is selected as desired by the user.

Figure 1: Block Diagram: Use of VSC7140 in Dual Repeater Mode

Internal

Fibre Channel

Subsystem

CRU

CRU

VSC7140

RX1

SO1

SO2

RX2