The DS2120A Ultra3 LVD SCSI Terminator is a Low Voltage Differential (LVD) terminator. If the device is connected in an LVD-only bus, the DS2120A will use LVD termination. If any single-ended (SE) or high-voltage differential (HVD) devices are connected to the bus, the DS2120A will isolate itself from the SCSI bus. This is accomplished automatically inside the part by sensing the voltage on the SCSI bus DIFFSENS line. For the LVD termination, the DS2120A integrates two current sources with nine precision resistor strings. Three DS2120A terminators are needed for a wide SCSI bus.
The DS2120A is a Low Voltage Differential (LVD) SCSI terminator designed for Ultra3 and Ultra 160 LVD-only SCSI buses. It automatically detects the bus mode (LVD, SE, or HVD) and isolates itself from the bus if non-LVD devices are present. The device integrates two current sources with nine precision resistor strings to provide termination.
| Differential Mode Termination Resistance | 100 Ohms (Min) to 110 Ohms (Typ) |
|---|---|
| Common Mode Termination Resistance | 110 Ohms (Min) to 190 Ohms (Max) |
| Output Capacitance | 3 pF |
| Operating Temperature | 0 to 70 °C |
| Termpower Voltage (LVD mode) | 2.7 V (Min) to 5.5 V (Max) |
| Thermal Shutdown Temperature | 150 °C |
Three DS2120A terminators are needed for a wide SCSI bus.
The DS2120A will automatically isolate itself from the SCSI bus.
A 4.7 uF capacitor is required between the Vref pin and ground.