ML6518

Fully monolithic IC solution providing active termination for 18 lines of the SCSI bus
Provides onboard support for hot-insertability on the SCSI bus
Low dropout voltage (1V) linear regulator, trimmed for accurate termination current
Low disconnect capacitance (typically < 5pF)
Logic pin with active pull-up to disconnect terminator from the SCSI bus
Current sinking capability in excess of 8.3mA per line to handle active negation driver overshoots above 2.85V
Negative clamping on all lines to handle signal assertion transients
Regulator can source 400mA and sink 150mA while maintaining regulation
Current limit and thermal shutdown protection

The ML6518 BiCMOS 18 line SCSI terminator provides active termination in SCSI systems using single-ended drivers and receivers. Active SCSI termination helps to effectively control analog transmission line effects such as ringing, noise, crosstalk, and ground bounce. In addition,the ML6518 provides support for hot insertability on the SCSI bus.

The ML6518 provides a V-I characteristic optimized to minimize transmission line effects during both signal negation and assertion using a MOSFET-based architecture. The desired V-I characteristic is achieved by trimming one resistor in the control block. Internal clamping controls signal assertion transients and provides current sink capability to handle active negation driver overshoots above 2.85V. ML6518 provides a 2.85V reference through an internal low dropout (1V) linear regulator.

The ML6518 also provides a disconnect function which effectively removes the terminator from the SCSI bus. The disconnect mode capacitance is typically less than 5pF per line. Current limiting and thermal shutdown protection are also included.