UC5603
9 LINE SCSI ACTIVE TERMINATOR
SLUS195A 鈥?MARCH 1997 鈥?REVISED OCTOBER 2000
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Complies with SCSI, SCSI鈥? and SPI鈥?
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Standards
6-pF Channel Capacitance during
Disconnect
100-碌A(chǔ) Supply Current in Disconnect Mode
Meets SCSI Hot Plugging
鈥?00-mA Sourcing Current for Termination
+400-mA Sinking Current for Active
Negation Drivers
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Logic Command Disconnects all
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Termination Lines
Trimmed Termination Current to 3%
Trimmed Impedance to 3%
Negative Clamping on all Signal Lines
Current Limit and Thermal Shutdown
Protection
description
The UC5603 provides 9 lines of active termination for a SCSI (Small Computers Systems Interface) parallel bus.
The SCSI standard recommends active termination at both ends of the cable segment.
The UC5603 provides a disconnect feature which, when opened or driven high, will disconnect all terminating
resistors, and disables the regulator; greatly reducing standby power. The output channels remain high
impedance even without Termpwr applied. A low channel capacitance of 6 pF allows units at interim points of
the bus to have little to no effect on the signal integrity.
Functionally the UC5603 is similar to its predecessor, the UC5601 鈥?18 line Active Terminator. Several electrical
enhancements were incorporated in the UC5603, such as a sink/source regulator output stage to accommodate
all signal lines at 5 V, while the regulator remains at its nominal value, reduced channel capacitance to 6 pF
typical, and as with the UC5601, custom power packages are utilized to allow normal operation at full power
conditions (1.2 watts).
functional block diagram
UDG-94049
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PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
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2000, Texas Instruments Incorporated
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鈥?/div>
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