DS2125
Ultra3 LVD/SE SCSI 15-Line Terminator
www.maxim-ic.com
GENERAL DESCRIPTION
The DS2125 Ultra3 LVD/SE SCSI terminator is both
a low-voltage differential (LVD) and single-ended
(SE) terminator. The multimode operation enables
the designer to implement LVD in current products
while allowing the end user SE backward
compatibility with legacy devices. If the device is
connected in an LVD-only bus, the DS2125 uses
LVD termination. If any SE devices are connected to
the bus, the DS2125 uses SE termination, which is
accomplished automatically inside the part by
sensing the voltage on the SCSI bus DIFFSENS line.
For the LVD termination, the DS2125 integrates two
current sources with 15 precision resistor strings. For
the SE termination, one regulator and 15 precision
110W resistors are used. Two DS2125 terminators
are needed for a wide SCSI bus.
FEATURES
摟
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Fully Compliant with Ultra3 SCSI
Provides Multimode Low-Voltage
Differential/Single-Ended (LVD/SE) Termination
for 15 Signal Line Pairs
Auto-Selection of LVD or SE Termination
5% Tolerance on SE and LVD Termination
Resistance
Low 3pF Power-Down Capacitance
On-Board Thermal-Shutdown Circuitry
SCSI Bus Hot-Plug Compatible
Fully Supports Actively Negated SE SCSI
Signals
PIN CONFIGURATION
TOP VIEW
HS_GND
HS_GND
HS_GND
V
REF
R1P
R1N
HS_GND
HS_GND
HS_GND
TPWR
R15N
R15P
APPLICATIONS
Raid Systems
SCSI Host Bus Adapter (HBA) Cards
Servers
SCSI Cables
Network Attached Storage (NAS)
Storage Area Networks (SANs)
R2P
R2N
R3P
R3N
R4P
12
13
14
15
16
17
18
19
20
21
22
23
24
25
11
10
9
8
7
6
5
4
3
2
1
48
47
R14N
R14P
R13N
R13P
R12N
R12P
R11N
R11P
R10N
R10P
R9N
R9P
Dallas
Semiconductor
DS2125
46
45
44
43
42
41
40
39
38
37
36
ORDERING INFORMATION
PART
DS2125
TEMP RANGE
0擄C to +70擄C
PIN-PACKAGE
48 LQFP
R4N
R5P
R5N
R6P
R6N
R7P
R7N
26
27
28
29
30
31
32
33
34
35
R8P
R8N
GND
HS_GND
HS_GND
HS_GND
ISO
DIFFSENSE
DIFF_CAP
HS_GND
HS_GND
HS_GND
LQFP
Note:
Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device
may be simultaneously available through various sales channels. For information about device errata, click here:
www.maxim-ic.com/errata.
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REV: 052604
MAXIM
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