UCC5673

SLUS438 - FEBRUARY 2000

FEATURES

• Auto Selection Multi-Mode Single

Ended or Low Voltage Differential

Termination

• 2.7V to 5.25V Operation

• Differential Failsafe Bias

• Built-in SPI-3 Mode Change Filter/

Delay

• Meets SCSI-1, SCSI-2, Ultra2 (SPI-2

LVD) and Ultra3/Ultra160 Standards

• Supports Active Negation

• 3pF Channel Capacitance

• Reversed Disconnect Polarity

Multimode (LVD/SE) SCSI 9 Line Terminator

1

27

16

DIFSENS

DIFSENS

REF 1.3V

ENABLE

3

L1–

52

2

L1+

52

L9–

L9+

56mV

+–

56mV

–+

124

110

SE GROUND

SWITCH

26

52

25

52

56mV

+–

56mV

–+

124

110

SE GROUND

SWITCH

REG

17

DIFFB

0.6V

2.1V

FILTER/

DELAY

28

TRMPWR

TRMPWR

LVD REF

1.25V

SOURCE/SINK

REGULATORS

SE REF

2.7V

ENABLE

SW1

10

µA

22

6

HS/GND

HS/GND

14

GND

13

DISCNCT

SE

DISCNCT

HPD

LVD

UP

OPEN

DOWN

DOWN

DOWN

UP

OPEN

OPEN

MODE

SW1

OTHER

SWITCHES

HPD

LVD

SE

BLOCK DIAGRAM

UDG-99162

DESCRIPTION

The UCC5673 Multi-Mode Low Voltage Differential and Single Ended Ter-

minator is both a single ended terminator and a low voltage differential ter-

minator for the transition to the next generation SCSI Parallel Interface

(SPI-3). The low voltage differential is a requirement for the higher speeds

at a reasonable cost and is the only way to have adequate skew budgets.

The automatic mode select/change feature switches the terminator be-

tween Single Ended or LVD Termination, depending on the bus mode. If

the bus is in High Voltage Differential Mode, the terminator lines transition

into a High Impedance state.

The UCC5673 is SPI-3, SPI-2, and SCSI-2 compliant. This device is of-

fered in a 28 pin TSSOP package to minimize the footprint. The UCC5673

is also available in a 36 pin MWP package.

Note: Indicated pinout is for 28 pin TSSOP package.