DS2107A Datasheet, PDF (1/7 Pages) Dallas Semiconductor – SCSI Terminator

DS2107A
DS2107A
SCSI Terminator
FEATURES
• Fully compliant with SCSI and SCSI-2 standards
• Backward compatible to the DS2107S
• Provides active termination for 9 signal lines
• Laser-trimmed 110 ohm termination resistors have
1% tolerance
• Low dropout voltage
• Power-down mode isolates termination resistors from
the bus
• Handles actively negated SCSI signals
• Onboard thermal shutdown circuitry
• 16-pin plastic SOIC (DS2107AS) and 20-pin plastic
thin SSOP (DS2107AE)
PIN ASSIGNMENT
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
DS2107AS 16-Pin SOIC (300 mil)
TERMPWR1
1
20
PD
HS–GND
2
19
VREF2
R1
3
18
HS–GND
R2
4
17
NC
R3
5
16
R9
R4
6
15
R8
R5
7
14
R7
HS–GND
8
13
R6
VREF1
9
GND
10
12
HS–GND
11
TERMPWR2
DS2107AE 20-Pin TSSOP (173 mil)
ACTUAL FOOTPRINT SIZE
.41”
.26”
.41”
.27”
DS2107AS
DS2107AE
DESCRIPTION
The SCSI-2 standard recommends the use of active ter-
minations at both ends of every cable segment in a
SCSI system with single-ended drivers and receivers.
The DS2107A SCSI Terminator, which is fully compliant
with the standard, 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 DS2107A integrates a regulator and
nine precise switched 110 ohm termination resistors
into a monolithic IC.
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