IMP5115

The IMP5115 SCSI terminator is part of IMP's family of high-performance, adaptive, non-linear mode SCSI products, which are designed to deliver true UltraSCSI performance in SCSI applications. The low voltage BiCMOS architecture employed in IMP5115 design offers performance superior to older linear passive and active techniques. IMP's SCSI IMP5115 termination architecture employs high-speed adaptive elements for each channel, thereby providing the fastest response possible - typically 35MHz, which is 100 times faster than the older linear regulator/terminator approach used by other manufacturers. Products using this older linear regulator approach have bandwidths which are dominated by the output capacitor and which are limited to 500KHz (see further discussion in the Functional Description section). This new architecture also eliminates the output compensation capacitor required in earlier terminator designs. Each is approved for use with SCSI-1, -2, -3, UltraSCSI and beyond -providing the highest performance alternative available today.

Another key improvement offered by the IMP5115 lies in its ability to insure reliable, error-free communications even in systems which do not adhere to recommended SCSI hardware design guidelines, such as the use of improper cable lengths and impedances. Frequently, this situation is not controlled by the peripheral or host designer and, when problems occur, they are the first to be made aware of the problem. The IMP5115 architecture is much more tolerant of marginal system integrations.

Recognizing the needs of portable and configurable peripherals, the IMP5115 has a TTL compatible sleep/disable mode. Quiescent current is typically 375µA in this mode, while the output capacitance is also less than 3pF. The obvious advantage of extended battery life for portable systems OF IMP5115 is inherent in the product's sleep-mode feature. Additionally, the disable function permits factory-floor or production-line configurability, reducing inventory and product-line diversity costs. Field configurability can also be accomplished without physically removing components which, often times results in field returns due to mishandling.

Reduced component count is also inherent in the IMP5115 architecture. Traditional termination techniques require large stabilization and transient protection capacitors of up to 20µF in value and size. The IMP5115 architecture does not require these components, allowing all the cost savings associated with inventory, board space, assembly, reliability, and component costs.