3

UCC5639

PIN DESCRIPTIONS

DIFFB: Diff sense filter pin should be connected at a

0.1

µF capacitor.

DIFFSENS: The SCSI bus Diff Sense line to detect what

types of devices are connected to the SCSI bus.

DISCNCT: Disconnect pin shuts down the terminator

when it is not at the end of the bus. The disconnect pin

high enables the terminator.

LINE

n–: Signal line active line for single ended or nega-

tive line in differential applications for the SCSI bus.

LINE

n+: Ground line for single ended or positive line for

differential applications for the SCSI bus.

REG: Regulator bypass pin, must be connected to a

4.7µF capacitor.

TRMPWR = 3.3V.

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNITS

Single Ended Termination Section

Impedance

Z

VL

V

IL

X

X

=

−

(.

)

02

, (Note 3)

102.3

110

117.7

Ω

Termination Current

Signal Level 0.2V, All Lines Low

–21

–24

–25.4

mA

Signal Level 0.5V

–18

–22.4

mA

Output Leakage

400

nA

Output Capacitance

Single Ended Measurement to Ground (Note 1)

3

pF

Single Ended GND SE Impedance

I= 10mA

20

60

Ω

Disconnect and Diff Buffer Input Section

DISCNCT Threshold

0.8

2.0

V

DISCNCT Input Current

10

30

Diff Buffer Single Ended to LVD Threshold

0.5

0.7

V

Diff Buffer LVD to HPD Threshold

1.9

2.2

V

DIFFB Input Current

–10

10

Note 1: Guaranteed by design. Not 100% tested in production.

Note 2:

[]

Z

V

II

CM

VCM

V

VCM

V

=

+−

12

06

06

.

–

(.

)

(

.

)

where VCM=voltage measured with L+ tied to L– and zero current applied