The DS2119M is a fully compliant LVD/SE SCSI terminator with SCSI SPI-2, SPI-3, SPI-4, Ultra160, and Ultra320 support. It provides multimode low-voltage differential/single-ended (LVD/SE) termination for nine signal-line pairs and has automatic LVD or SE termination selection. The terminator is SCSI-bus hot-plug compatible and features onboard thermal-shutdown circuitry. It fully supports actively negated SE SCSI signals. Three DS2119M terminators are needed for a wide SCSI bus.
The DS2119M is an Ultra3 LVD/SE SCSI terminator designed for use in SCSI bus configurations. It provides multimode termination that automatically selects between Low-Voltage Differential (LVD) and Single-Ended (SE) modes based on the voltage sensed on the DIFFSENS line, ensuring compatibility with both legacy SE devices and modern LVD/Ultra160/Ultra320 systems.
The device integrates precision resistor strings and current sources for LVD termination, as well as a regulator and resistors for SE termination. It features onboard thermal shutdown, low power-down capacitance (3pF), and supports actively negated SE SCSI signals. The datasheet details functional descriptions, recommended operating conditions, electrical characteristics, and package dimensions.
| Termination Resistance (SE) | 110 Ohms typical |
|---|---|
| SE Voltage Reference | 2.85V typical |
| Output Capacitance | 3 pF |
| Thermal Shutdown Temperature | 150 C |
| Operating Temperature Range | 0 to +70 C |
The device automatically selects the appropriate termination mode by sensing the voltage on the SCSI bus DIFFSENS line.
Three DS2119M terminators are required to terminate a wide SCSI bus.
A 4.7uF capacitor is required between the Vref pin and ground.