UCC5640

SLUS314C – JANUARY 2000 – REVISED JUNE 2003

LOW VOLTAGE DIFFERENTIAL (LVD) SCSI 9LINE TERMINATOR

1

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FEATURES

/ Ultra160 (Fast-80) and SPI-4 (Fast-160)

Ultra320 Standards

DESCRIPTION

The UCC5640 is an active terminator for low voltage

differential (LVD) SCSI networks. This LVD only design

allows the user to reach peak bus performance while

reducing system cost. The device is designed as an

active Y-terminator to improve the frequency response

of the LVD bus. Designed with a 1.5-pF channel

capacitance, the UCC5640 allows for minimal bus

loading for a maximum number of peripherals. With the

UCC5640, the designer will be able to comply with the

Fast-40 SPI-2, Fast-80 SPI-3 and Fast-160 SPI-4

specifications. The UCC5640 also provides a much

needed system migration path for ever improving SCSI

system standards. This device is available in the 24-pin

TSSOP and 28-pin TSSOP for ease of layout use.

The UCC5640 is not designed for use in single ended

(SE) or high voltage differential (HVD) systems.

BLOCK DIAGRAM

UDG–98181

REF 1.25V

15

DISCNCT

27

LVD*

1

REG

11

DIFFB

4

L1–

3

L1+

26

L9–

25

L9+

56mV

SOURCE/SINK REGULATOR

REF 1.3V

1.3V + 0.1V

0.7V > 0.5V

2.4V > 1.9V

HIGH IMPEDANCE RECEIVER

EVEN WITH POWER OFF

SINGLE

ENDED

HIGH POWER

DIFFERENTIAL

12

DIFSENS

SOURCE 5– 15mA

SINK 200 µA MAXIMUM (NOISE LOAD)

OPEN CIRCUIT ON POWER OFF

OR OPEN CIRCUIT IN A

DISABLED TERMINATOR MODE

10µA

28

TRMPWR

124

124

52

52

52

52

14

GND

2.7V to 5.25V

56mV

+

–

–

+

56mV

+

–

56mV

–

+

*28 pin package only

These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam

during storage or handling to prevent electrostatic damage to the MOS gates.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of Texas Instruments

standard warranty. Production processing does not necessarily include

testing of all parameters.

Copyright

 2003, Texas Instruments Incorporated