DS21S07A
DS21S07A
SCSI Terminator
FEATURES
PIN ASSIGNMENT
TERMPWR1
R1
R2
R3
R4
R5
VREF1
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
PD
VREF2
NC
R9
R8
R7
R6
TERMPWR2
•
Fully
SCSI
compliant with SCSI–1, Fast SCSI and Ultra
•
Backward compatible to the DS2107 and DS2107A
•
Provides active termination for nine signal lines
•
Laser–trimmed 110
2% tolerance
ohm termination resistors have
•
Low dropout voltage regulator
•
Power–down
from the bus
mode isolates termination resistors
DS21S07AS 16–PIN SOIC (300 MIL)
TERMPWR1
HS–GND
R1
R2
R3
R4
R5
HS–GND
VREF1
GND
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
PD
VREF2
HS–GND
NC
R9
R8
R7
R6
HS–GND
TERMPWR2
•
SCSI bus hot plug–compatible
•
Fully supports actively negated SCSI signals
•
Onboard thermal shutdown circuitry
•
16–pin plastic SOIC (DS21S07AS) and 20–pin plastic
TSSOP (Thin Shrink Small Outline Package)
(DS21S07AE)
DS21S07AE 20–PIN TSSOP (173 MIL)
ACTUAL FOOTPRINT SIZE
.41”
.26”
.41”
.27”
DS21S07AS
DS21S07AE
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 DS21S07A SCSI Terminator, which is fully com-
pliant with these standards, enables the designer to
gain the benefits of active termination: greater immunity
to voltage drops on the TERMPWR (TERMination
PoWeR) line, enhanced high-level noise immunity, in-
trinsic TERMPWR decoupling, and very low quiescent
current consumption. The DS21S07A integrates a reg-
ulator and nine precise switched 110 ohm termination
resistors into a monolithic IC. The DS21S07A can be
electrically isolated from the SCSI bus without physical
removal from the SCSI device.
022798 1/7
ETC [ ETC ]
