UNITRODE UCC5617 Technical data

18-Line SCSI Terminator (Reverse Disconnect)
UCC5617
FEATURES
Complies with SCSI, SCSI-2, SCSI-3,
SPI and FAST-20 Standards
2pF Channel Capacitance During
Disconnect
50mA Supply Current in Disconnect
Mode
110
Trimmed Impedance to 5%
Thermal Shutdown
Current Limit
Termination
SCSI Hot Plugging Compliant, 10nA Typical
+400mA Sinking Current for Active Negation
–650mA Sourcing Current for Termination
DESCRIPTION
The UCC5617 provides 18 lines of active termination for a SCSI (Small Computers Systems Interface) parallel bus. The SCSI standard recom mends and Fast-20 (Ultra) requires active termination at both ends of the cable.
Pin for pin compatible with the UC5609, the UCC5617 is ideal for high per formance 5V SCSI systems, Termpwr 4.0-5.25V. During disconnect the supply current is only 50 powered systems.
The UCC5617 is designed with a low channel capacitance of 2pF, which eliminates effects on signal integrity from disconnected terminators at in terim points on the bus.
The power amplifier output stage allows the UCC5617 to source full termi nation current and sink active negation current when all termination lines are actively negated.
The UCC5617, as with all Unitrode terminators, is completely hot pluggable and appears as high impedance at the terminating channels with TRMPWR = 0V or open.
Internal circuit trimming is utilized, first to trim the 110 then most importantly, to trim the output current as close to the maximum SCSI-3 specification as possible, which maximizes noise margin in fast SCSI operation.
A typical, which makes the IC attractive for lower
impedance, and
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BLOCK DIAGRAM
This device is offered in low thermal resistance versions of the industry standard 28 pin wide body SOIC.
Patented Circuit Design
SLUS351A - APRIL 1997 - REVISED AUGUST 2002
UDG-96073
UCC5617
CONNECTION DIAGRAMS
SOIC-28 (Top View) DWP Package
* DWP package pin 28 serves as signal ground; pins 7, 8, 9, 20, 21, 22 serve as heatsink/ground.
ABSOLUTE MAXIMUM RATINGS
TEMPWR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +7V
Signal Line Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +7V
Regulator Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . 1A
Storage Temperature . . . . . . . . . . . . . . . . . . . –65°C to +150°C
Operating Junction Temperature . . . . . . . . . . –55°C to +150°C
Lead Temperature (Soldering, 10 Seconds) . . . . . . . . . . 300°C
All currents are positive into, negative out of the specified terminal. Consult Packaging Section of Databook for thermal limitations and considerations of packages.
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