UCC5614DP

The UCC5614DP from Unitrode is an active termination integrated circuit designed to provide 9 lines of termination for Small Computer System Interface (SCSI) parallel buses. It complies with SCSI, SCSI-2, and SPI-2 single-ended standards, making it suitable for high-performance SCSI systems, particularly those operating at 3.3-V. The device features a low operating voltage range of 2.7-V to 5.25-V, supported by an integrated 0.1-V drop-out regulator and a 2.7-V reference.

Key features include an ultra-low channel capacitance of 1.8 pF during disconnect, which helps maintain signal integrity on the bus. In disconnect mode, the supply current drops to a typical 0.5 µA, making it attractive for battery-powered applications. The UCC5614DP offers programmable termination with impedance values of 110 Ohms and 2.5 kOhms. It also provides -400 mA sourcing current for termination and +400 mA sinking current for active negation drivers. The termination current is trimmed to 4% and impedance to 7%, with built-in current limit and thermal shutdown protection for reliability. The device meets SCSI hot-plugging requirements.

This active termination IC is ideal for ensuring proper termination at both ends of the SCSI cable segment, as recommended by the standard. Its design minimizes signal integrity issues from disconnected terminators on the bus.