DS2119M
Ultra3 LVD/SE SCSI Terminator
www.maxim-ic.com
FEATURES
Fully compliant with SCSI SPI-2, SPI-3,
SPI-4, Ultra160, and Ultra320
Provides multimode low-voltage
differential/single-ended (LVD/SE)
termination for nine signal-line pairs
Auto-selection of LVD or SE termination
5% tolerance on SE and LVD termination
resistance
Low power-down capacitance of 3pF
Onboard thermal-shutdown circuitry
SCSI-bus hot-plug compatible
Fully supports actively negated SE SCSI
signals
PIN ASSIGNMENT
VREF
RIP
RIN
R2P
R2N
HS GND
R3P
R3N
R4P
R4N
R5P
R5N
ISO
GND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
TPWR
TPWR
R9N
R9P
R8N
R8P
HS GND
R7N
R7P
R6N
R6P
DIFF_CAP
DIFFSENSE
MSTR/SLV
DS2119ME 28-Pin TSSOP
DESCRIPTION
The DS2119M 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 DS2119M will use LVD termination. If any SE devices are connected
to the bus, the DS2119M will use SE termination. This is accomplished automatically inside the part by
sensing the voltage on the SCSI bus DIFFSENS line.
For the LVD termination, the DS2119M integrates two current sources with nine precision resistor
strings. For the SE termination, one regulator and nine precision 110Ω resistors are used. Three
DS2119M terminators are needed for a wide SCSI bus.
REFERENCE DOCUMENTS
Small Computer Systems Interface (SCSI-3)
Small Computer Systems Interface (SCSI-3)
Small Computer Systems Interface (SCSI-3)
Small Computer Systems Interface (SCSI-3)
SCSI Parallel Interface (SPI)
SCSI Parallel Interface 2 (SPI-2)
SCSI Parallel Interface 3 (SPI-3)
SCSI Parallel Interface 4 (SPI-4)
Project: 0855-M, 1995
Project: 1142-M, 1998
Project: 1302-D, 1999
Project: 1365-D, 200x
Available From:
American National Standards Institute (ANSI) Phone: (212) 642-4900
Global Engineering Documents 15 Inverness Way East; Englewood, CO 80112 Phone: (800) 854-7179
1 of 9
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DALLAS [ DALLAS SEMICONDUCTOR ]
