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112099

FEATURES

Fully compliant with SCSI-1, Fast SCSI and

Ultra SCSI

Functional drop in replacement for the

DS2106

Complimentary part to DS21T07 for wide

SCSI

Provides active termination for 18 signal lines

5% tolerance on termination resistors and

voltage regulator

5% tolerance on termination current

Low power down capacitance of 3 pF

Onboard thermal shutdown circuitry

SCSI bus hot plug compatible

Fully supports actively negated SCSI signals

PIN ASSIGNMENT

DESCRIPTION

Fast SCSI and Ultra SCSI require the use of active terminations at both ends of every cable segment in a

SCSI system with single-ended drivers and receivers. Ultra SCSI requires support of active negation and

hot plugging. The DS21T06 is fully compliant with these standards.

The DS21T06 integrates a low dropout regulator and 18 precise switched 110 ohms termination resistors

into a 28-pin 300-mil SOIC package.

Active termination provides greater immunity to voltage drops on the TERMPWR (TERMination

PoWeR) line, enhanced high-level noise immunity, intrinsic TERMPWR decoupling, and very low

quiescent current consumption. One DS21T06 can be used to terminate the Narrow SCSI bus, or a

DS21T07 can be used with a DS21T06 for termination of a Wide SCSI bus.

REFERENCE DOCUMENTS

SCSI-2 (X3.131-1994)

SCSI-3 Parallel Interface (X3T10/855D)

SCSI-3 Fast–20 (X3T10/1071D)

Available from: Global Engineering Documents

15 Inverness Way East

Englewood, CO 80112-5704

Phone: (800) 854-7179,(303) 792-2181

Fax: (303) 792-2192

DS21T06

SCSI Terminator

www.dalsemi.com

1

2

3

4

5

6

7

8

9

10

11

12

24

27

26

25

23

22

21

20

19

18

17

16

R17

R16

R15

NC

HS-GND

NC

R13

R12

R11

R10

R14

R2

R3

R4

HS-GND

HS-GND

NC

R6

R7

R8

R9

TPWR

R5

DS21T06S 28-Pin SOIC (300-mil)

13

14

28

15

PD

R1

GND

R18