© VITESSE SEMICONDUCTOR CORPORATION

Page 1

8/31/98

741 Calle Plano, Camarillo, CA 93012 • 805/388-3700 • FAX: 805/987-5896

VITESSE

SEMICONDUCTOR CORPORATION

Advance Product Information

VSC7128

Hex Port Bypass Circuit / Dual Repeater

for 1.0625 Gb/s FC-AL Disk Arrays

G52177-0, Rev. 2.3

Features

General Description

The VSC7128 contains six Port Bypass Circuits (PBCs), dual embedded Clock Recovery Unit repeaters

(CRU) and dual Signal Detect Units (SDU). These functions are integrated into a single part to minimize circuit

size, part count, cost, high frequency routing and jitter accumulation. Together, they allow for optimized designs

of FC-AL JBOD systems that provide resiliency and hot insertion/removal of disk drives. The PBCs configure

the FC-AL loop to either include or exclude each drive.

Repeaters retime the incoming signal thereby attenu-

ating jitter so that downstream devices see high amplitude, low jitter signals. The SDUs determine whether the

output of the CRU is a valid Fibre Channel signal. Disk drives are connected directly to the LSO/LSI/SEL pins

while the IN/OUT pins can be connected to any FC-AL devices.

VSC7128 Block Diagram

• Supports ANSI X3T11 1.0625Gb/s FC-AL Disk

Attach for Resiliency

• Dual Repeaters (CRUs) Improve Signal Quality

• Six Port Bypass Circuits (PBCs) for Resiliency

• Dual Digital Signal Detect Units (SDUs)

• Fully Differential for Minimum Jitter

• Selectable REFCLK: 53.125 / 106.25MHz

• TTL Bypass Select

• 3.3V Supply, 1.3W

• 64-Pin, 14 mm Thermally Enhanced PQFP

1

0

PBC1

REFCLK

SDU1

CRU1

SDU2

CRU2

OUT1+

OUT1-

1

0

IN2+

IN2-

DISK

DRIVE

#1

(106/53 MHz)

IN1+

IN1-

1

0

PBC2

DISK

DRIVE

#2

1

0

PBC3

DISK

DRIVE

#3

1

0

PBC4

DISK

DRIVE

#4

1

0

PBC5

DISK

DRIVE

#5

1

0

PBC6

DISK

DRIVE

#6

OUT2+

OUT2-

MUX7

1

0

MUX8

CMU

FAILSEL

RFSEL