FEATURES
·
Fully Compliant With
Ultra2, Ultra3 and Ultra320 SCSI Standards.
·
Build In Low Pass
Filter On DIFF_IN Pin.
·
Low Terminal
Capacitance of 2pF
·
Fast Response
Regulator, No External Capacitors Required.
·
Auto–selection of LVD
or SE Mode
·
Provides Multi-mode
Termination for 9 Signal Line Pairs
·
Differential Fail-safe
Bias.
·
Low Power with On
Demand Consumption Only.
·
SCSI Bus Hot Plug
Compatible
·
Fully Supports Actively
Negated SE SCSI Signals
DESCRIPTION
The ST18-28 multi-mode SCSI
Terminator is both a Low Voltage Differential (LVD) and Single–Ended (SE)
terminator for the transition to the next generation SCSI bus interface. If the
device is connected in an LVD only bus, the ST18-28 will use LVD termination. If
any SE devices are connected to the bus, the ST18-28 will use SE termination.
Automatic mode selection is achieved through voltage detection on the DIFFSENSE
line. For the LVD termination, the ST18-28 integrates two regulated supplies
with nine precision resistor strings. For the SE termination, one regulator and
nine precision 110 ohm resistors are used. The ST18-28 cannot be used with SCSI
differential EIA485. ST18-28 will shutdown when it sees high voltage on the
line in order to protect the device.
The external capacitors may
be eliminated with the fast response voltage regulator design on VSE pin and
the build in low-pass filter on DIFF_IN pin.