The UCC5610 provides 18 lines of active termination for a SCSI (small computer systems interface) parallel bus. The SCSI standard recommends active termination at both ends of the cable. The UCC5610 is ideal for high performance 3.3-V SCSI systems. The key features contributing to such low operating voltage are the 0.1-V drop-out regulator and the 2.75-V reference. During disconnect the supply current is typically only 0.5 A, which makes the IC attractive for battery powered systems. The UCC5610 is designed with an ultralow-channel capacitance of 1.8 pF, which eliminates effects on signal integrity from disconnected terminators at interim points on the bus. The UCC5610 can be programmed for either a 110- or 2.5-k termination. The 110- termination is used for standard SCSI bus lengths and the 2.5-k termination is typically used in short bus applications. When driving the TTL compatible DISCNCT pin directly, the 110- termination is connected when the DISCNCT pin is driven low, and disconnected when driven high. When the DISCNCT pin is driven through an impedance between 80 k and 150 k, the 2.5-k termination is connected when the DISCNCT pin is driven low, and disconnected when driven high.