DS2120E

Ultra3 LVD SCSI Terminator

Data Sheet (Rev. 2)

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Overview

Fully Compliant with Ultra3, Ultra160, Ultra320, and Ultra2 (LVD only) SCSI

Provides Low-Voltage Differential (LVD) Termination for Nine Signal Line Pairs

Zero Temperature Coefficient Termination Resistors

Autoselection of LVD Termination

5% Tolerance on LVD Termination Resistance

Low Power-Down Capacitance of 3pF

Built-In Mode Change Filter/Delay

On-Board Thermal Shutdown Circuitry

SCSI Bus Hot Plug Compatible

The DS2120 Ultra3 LVD SCSI terminator is a low-voltage differential (LVD) terminator. If the device is connected in an LVD-only bus, the DS2120 uses LVD termination. If any single-ended (SE) or highvoltage differential (HVD) devices are connected to the bus, the DS2120 disconnects from the bus. This is accomplished inside the part automatically by sensing the voltage on the SCSI bus DIFFSENS line.

For the LVD termination, the DS2120 integrates two current sources with nine precision resistor strings. Three DS2120 terminators are needed for a wide SCSI bus.

Applications