SiP5678

Vishay Siliconix

New Product

Document Number: 73100

S-41843—Rev. A, 11-Oct-04

www.vishay.com

1

15-Line SCSI Bus Terminators

FEATURES

D Auto Selection of S/E or LVD SCSI Termination

D 2.7-V to 5.25-V TERMPWR Range

D Meets SCSI-1, SCSI-2, SPI-2 (ULTRA-2), SPI-3

(ULTRA-160) and SPI-4 (ULTRA-320) Standards

D Integrated SPI-3 Mode Change Delay Filter

D Differential Failsafe Bias

D Thermal Package

D On-Chip Thermal Shutdown Circuit

D Active Negation

D Hot Swap Compatible

D Pin Compatible with UCC5638

D Lead (Pb)-Free SQFP-48 Package

APPLICATIONS

D Disk Array (RAID)

D Storage Area Networks (SAN)

D Network Attached Storage (NAS)

D SCSI Cable

D Server and Workstation

D Industrial Computers

D High-End Personal Computers

DESCRIPTION

The SiP5678 provides active bus termination suitable for all

SCSI bus operational modes from SCSI-1 through SPI-4 (Ultra

SCSI 320). The termination includes impedance matching of

the Ultra SCSI bus to minimize signal reflections from the end

of the bus, as well as required SCSI bus biasing for either S/E

(single ended) or LVD (low voltage differential) operation.

The SiP5678 has fifteen (15) output channels (T1−T15). Each

output channel provides termination for one SCSI data signal,

parity signal or control signal. Two SiP5678 ICs provide

complete termination for a wide SCSI bus.

An integrated mode change delay filter in the SiP5678

eliminates the need for a bulky 4.7-mF low pass filter capacitor

to be compliant with SPI-3 mode change timing requirements.

The SiP5678 senses the operational state of the SCSI bus via

the DIFFSENS bus signal, and automatically switches to S/E

or LVD operation as required. It cannot be used on an HPD

(high power differential) SCSI bus, and goes into high

impedance mode when the voltage on the DIFFSENS line

indicates HPD operation. The SiP5678 also presents high

impedance to the SCSI bus if the DISABLE pin is asserted, or

if TERMPWR is removed from the IC.

The SiP5678 is available in a lead (Pb)-free SQFP-48

package for operation over the temperature range of 0 to

70 _C.

FUNCTIONAL BLOCK DIAGRAM

(Page 6) for detailed

descriptions of SCSI Terminator

Impedance Circuits in LVD and

S/E modes of operation.

36

34

3

Heat Sink GND Pins

GND

REG

1.3 V

4

9

33

28

10

27

Current Limited

Source/Sink

Regulator

Comparators

and

Delay Filter

V t 0.5 = S/E

0.7 t V t1.9 = LVD

V u 2.4 = HPD

TERMPWR

35

2

1

48

47

Current Limited

Source/Sink

Regulator

Mode Control And

Enable/Disable

Circuitry

SCSI

Terminator

Impedance

Circuits

10 mA

MODE

DISABLE

DIFFS

T1N

T1P

T15P

T15N