DS2118M

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DETAILED DESCRIPTION

The DS2118M 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 DS2118M will use LVD termination. If any SE devices are connected

to the bus, the DS2118M 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 DS2118M integrates two current sources with nine precision resistor

strings. For the SE termination, one regulator and nine precision 110Ω resistors are used. Three

DS2118M terminators are needed for a wide SCSI bus.

REFERENCE DOCUMENTS

Small Computer Systems Interface (SCSI-3) SCSI Parallel Interface (SPI)

Project: 0855-M, 1995

Small Computer Systems Interface (SCSI-3) SCSI Parallel Interface 2 (SPI-2) Project: 1142-M, 1998

Small Computer Systems Interface (SCSI-3) SCSI Parallel Interface 3 (SPI-3) Project: 1302-D, 1999

Small Computer Systems Interface (SCSI-3) SCSI Parallel Interface 4 (SPI-4) 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