Texas Instruments UC5603 Data Handbook

SLUS195B − MARCH 1997 − REVISED NOVEMBER 2003

Complies with SCSI, SCSI−2 and SPI−2 Logic Command Disconnects all Standards Termination Lines 6-p F Channel Capacitance during Trimmed Termination Current to 3% Disconnect

Trimmed Impedance to 3%

100-µA Supply Current in Disconnect Mode

Negative Clamping on all Signal Lines

Meets SCSI Hot Plugging

Current Limit and Thermal Shutdown −400-m A Sourcing Current for Termination Protection

+400-m A Sinking Current for Active Negation Drivers

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 p F 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 − 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 p F 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

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

1www.ti.com