DS2105 Datasheet, PDF (1/7 Pages) Dallas Semiconductor – SCSI Terminator

DS2105
DS2105
SCSI Terminator
FEATURES
• Fully compliant with SCSI–1, Fast SCSI and Ultra
SCSI
• Functionally compatible to the DS21S07A, targeted
for high volume applications
• Provides active termination for nine signal lines
• Laser–trimmed 110 ohm termination resistors have
5% tolerance
• Low dropout voltage
• Power–down mode isolates termination resistors
from the bus
• Fully supports actively negated SCSI signals
• Onboard thermal shutdown circuitry
• 16–pin plastic SOIC (DS2105)
PIN ASSIGNMENT
TERMPWR1
R1
1
16
2
15
PD
VREF2
R2
3
14
R9
R3
4
13
R8
R4
5
12
R7
R5
6
11
R6
VREF1
7
10
NC
GND
8
9
TERMPWR2
DS2105Z 16–PIN SOIC (150 MIL)
TERMPWR1
1
R1
2
16
PD
15
VREF2
R2
3
14
NC
R3
4
13
R9
R4
5
12
R8
R5
6
11
R7
VREF1
7
10
R6
GND
8
9
TERMPWR2
DS2105S 16–PIN SOIC (300 MIL)
DESCRIPTION
Fast SCSI and Ultra SCSI require the use of active ter-
minations at both ends of every cable segment in a
SCSI system with single–ended drivers and receivers.
The DS2105 SCSI Terminator, which is fully compliant
with these standards, enables the designer to gain the
benefits of active termination: greater immunity to volt-
age drops on the TERMPWR (TERMination PoWeR)
line, enhanced high–level noise immunity, intrinsic
TERMPWR decoupling, and very low quiescent current
consumption. The DS2105, which integrates a regula-
tor and nine precise switched 110 ohm termination re-
sistors into a monolithic IC, is a functionally compatible
version of the DS21S07A. With relaxed output current
and termination tolerances, the DS2105 is intended for
high volume applications which require active termina-
tion but not the high performance of the DS21S07A.
The DS2105 is offered in both 300 mil and 150 mil SOIC
packages.
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