SS7519 Datasheet, PDF (1/5 Pages) Silicon Standard Corp. – Multi-mode SCSI Terminator

FEATURES
!" Meets SCSI-1, SCSI-2, Ultra3 and
Ultra320 Standards.
!" Auto-selectable Multimode single-ended
or Low Voltage Differential termination.
!" Current limit and thermal shutdown
protection.
!" Ground driver integrated for
single-ended operation
!" Compatible with active-negation drivers.
SS7519
Multi-mode SCSI Terminator
Single-Ended resistor will maintain 110Ω ± 5%.
For LVD termination, the SS7519
integrates two current sources with nine
accuracy resistor strings. This architecture yields
a 105Ω ±5% differential and 226Ω ±10%
common mode impedance. A fail-safe bias of
110mV is sustained when no drivers are
connected to the SCSI bus. If the SS7519
detects a HVD SCSI device on the bus, all the
signals will be set to a high impedance state.
DESCRIPTION
The SS7519 multimode SCSI terminator is
both a single-ended and a low voltage
differential terminator that meets the
specifications of SCSI Parallel Interface (SPI-4).
The SS7519 also provides backward
VRFF
compatibility to the SCSI-1, SCSI-2 and
Single-Ended specifications. The Multimode
terminator contains all the functions required to
terminate and auto detect for SCSI devices
without hardware fluctuation. Auto-Selectable is
achieved by using voltage detection on the
DIFFSENSE signal. The SS7519 senses the
DIFFSENSE line while sourcing the
DIFFSENSE signal with LVD levels. The
DIFFSENSE line being grounded indicates that
RIP
RIN
R2P
R2N
HS GND
R3P
R3N
R4P
R4N
R5P
R5N
ISO
GND
one or more SE devices are attached on the bus.
The SS7519 switches to the termination mode
that is appropriate for the bus based on the value
of the DIFFSENSE input voltage.
For the Single-Ended termination, the active
terminator will pull R_XN to 2.85V and R_XP to a
hard ground. The SS7519 can sink 22mA
per line as required by the SCSI specification. The
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SS7519 - TSSOP28
Rev.2.01 6/06/2003
www.SiliconStandard.com
TPWR
TPWR
R9N
R9P
R8N
R8P
HS GND
R7N
R7P
R6N
R6P
DIFF_CAP
DIFFSENSE
M/S
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