UC5601
SCSI Active Terminator
FEATURES
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Complies with SCSI, SCSI-2
Standards
10pF Channel Capacitance During
Disconnect
Active Termination for 18 Lines
Logic Command Disconnects all
Termination Lines
Low Supply Current in Disconnect
Mode
Trimmed Regulator for Accurate
Termination Current
Current Limit and Thermal
Shutdown Protection
110 Ohm Termination
Meets SCSI Hot Plugging
DESCRIPTION
The UC5601 provides precision resistive pull-up to a 2.9V reference for all
18 lines in a Small Computer Systems Interface (SCSI) bus cable. The
SCSI-2 standard recommends active termination at both ends of every ca-
ble segment utilizing single ended drivers and receivers.
Internal circuit trimming is utilized, first to reduce resistor tolerances to
±
3%
and then to adjust the regulator’s output voltage to insure termination cur-
rent accuracy of
±
3%.
The UC5601 provides a disconnect feature which, upon a logic command,
disconnects all terminating resistors, and turns off the regulator; greatly re-
ducing standby power.
Other features include negative clamping on all signal lines, 20mA of active
negation sink current capability, regulator current limiting, and thermal shut-
down protection.
This device is offered in low thermal resistance versions of the industry
standard 28 pin wide body SOIC and PLCC, as well as a 24 pin DIL plastic
package.
BLOCK DIAGRAM
UDG-94060
Circuit Design Patented
10/94
TI [ TEXAS INSTRUMENTS ]
