DS21T06 Dallas Semiconducotr, DS21T06 Datasheet

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DS21T06

Manufacturer Part Number
DS21T06
Description
SCSI Terminator
Manufacturer
Dallas Semiconducotr
Datasheet
www.DataSheet4U.com
FEATURES
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
www.dalsemi.com
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
1 of 6
PIN ASSIGNMENT
HS-GND
HS-GND
TPWR
DS21T06S 28-Pin SOIC (300-mil)
NC
PD
R6
R7
R8
R9
R1
R2
R3
R4
R5
1
10
11
12
13
2
3
5
6
7
8
9
14
4
SCSI Terminator
26
25
23
22
21
20
19
18
17
16
15
28
27
24
R16
R15
R14
NC
HS-GND
NC
R13
R12
R11
R10
V
GND
R18
R17
DS21T06
REF
112099

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DS21T06 Summary of contents

Page 1

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

Page 2

... Figure 2 details a typical SCSI bus configuration 8-bit data SCSI bus (Narrow SCSI), one DS21T06 is needed for proper termination of the 18 active signal lines. One DS21T06 and one DS21T07 can be used to terminate the 27 active signal lines in a 16- bit data SCSI bus (Wide SCSI). ...

Page 3

... C2 = 2.2 F tantalum or 4.7 F aluminum C3 = 0.01 F ceramic 2. If the DS21T06 embedded into a peripheral that will act as a target on a SCSI bus recommended that TERMPWR be derived from the SCSI cable, not generated locally. In this configuration power failure occurs in the peripheral, it will not affect the bus. ...

Page 4

... GND DESCRIPTION Power Down. When tied low, the DS21T06 enters power-down mode. Contains an internal 50 kΩ pull-up. Tie low to deactivate the DS21T06. Tie high or leave open circuited to activate the DS21T06. Signal Termination 1. 110 ohms termination. Connect to SCSI bus signal lines. Heat Sink Ground. Internally connected to the mounting pad. Should be either grounded or electrically isolated from other circuitry ...

Page 5

... Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. The Dallas Semiconductor DS21T06 is built to the highest quality standards and manufactured for long term reliability. All Dallas Semiconductor devices are made using the same quality materials and manufacturing methods ...

Page 6

NOTES: 1. 4.00V < TERMPWR < 5.50V. 2. 0.0V < signal lines < TERMPWR. 3. All signal lines = 0.0V. 4. All signal lines open. 5. Power-down enabled Guaranteed by design; not production tested 0.2V. ...

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