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
·
Un-Leaded TSSOP-28
Package.
DESCRIPTION
ST18-28UL is packaged in an
Un-Leaded TSSOP package. It is function and performance compatible with
ST18-28. It is both a Low Voltage Differential (LVD) and Single–Ended (SE)
terminator to cover both the earlier and the latest Ultra160 and Ultra320 SCSI
bus interfaces. If the device is connected in an LVD only bus, the ST18-28UL
will use LVD termination. If any SE devices are connected to the bus, the
ST18-28UL will use SE termination. Automatic mode selection is achieved through
voltage detection on the DIFFSENSE line. For the LVD termination, the ST18-28UL
integrates two regulated supplies with nine precision resistor strings. For the
SE termination, one regulator and nine precision 110 ohm resistors are used.
The ST18-28UL cannot be used with SCSI differential EIA485. ST18-28UL 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.