UC5603,pdf(9-Line SCSI Active

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 – 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.