●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 (1.2 watts).
●Internal circuit trimming is utilized, first to trim the impedance to a 3% tolerance, and then most importantly, to trim the output current to a 3% tolerance, as close to the max SCSI spec as possible, which maximizes noise margin in fast SCSI operation.
●Other features include negative clamping on all signal lines to protect external circuitry from latch-up, thermal shutdown and current limit.
●This device is offered in low thermal resistance versions of the industry standard 16 pin narrow body SOIC.
● Complies with SCSI, SCSI2 and SPI2 Standards
● 6-pF Channel Capacitance during Disconnect
● 100-µA Supply Current in Disconnect Mode
● Meets SCSI Hot Plugging
● 400-mA Sourcing Current for Termination
● +400-mA Sinking Current for Active Negation Drivers
● Logic Command Disconnects all Termination Lines
● Trimmed Termination Current to 3%
● Trimmed Impedance to 3%
● Negative Clamping on all Signal Lines
● Current Limit and Thermal Shutdown Protection
Part 3D Model
