Key Features

x

SCSI plug and play

— Dual disconnect pins

— Logic LOW disconnects lines

x

Hot swap compatible

x

Ultra-Fast response for Fast-20 SCSI applications

x

35MHz channel bandwidth

x

3.5V operation

x

Less than 3pF output capacitance

x

375µA disable-mode current

x

Thermally self limiting

x

No external compensation capacitors

x

Implements 8-bit or 16-bit (wide) applications

x

Compatible with active negation drivers

(60mA/channel)

x

Compatible with passive and active terminations

x

Approved for use with SCSI 1, 2, 3 and UltraSCSI

Block Diagrams

DISCONNECT 1

DISCONNECT 2

Current

Biasing

Circuit

Thermal

Limiting

Circuit

24mA Current

Limiting Circuit

Term Power

DATA OUTPUT

PIN DB (0)

1 of 9 Channels

2.85V

5218_01.eps

9-Line Plug and Pla

SCSI T

or

The 9-channel IMP5218 SCSI terminator is part of IMP's family of high-

performance SCSI terminators that deliver true UltraSCSI performance.

The BiCMOS design offers superior performance over first generation

linear regulator/resistor based terminators.

The IMP5218 has two disconnect pins for SCSI Plug and Play (PnP)

applications.

IMP's new 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 termi-

nator approach. The bandwidth of terminators based on the older

regulator/resistor terminator architecture is limited to 500kHz since a

large output stabilization capacitor is required. The IMP architecture

eliminates the external output compensation capacitor and the need

for transient output capacitors while maintaining pin compatibility

with first generation designs. Reduced component count is inherent

with the IMP5218.

The IMP5218 architecture tolerates marginal system designs. A key

improvement offered by the IMP5218 lies in its ability to insure reliable,

error-free communications even in systems which do not adhere to rec-

ommended SCSI hardware design guidelines, such as improper cable

lengths and impedance. Frequently, this situation is not controlled by the

peripheral or host designer.

For portable and configurable peripherals, the IMP5218 can be placed in

a sleep mode with two disconnect signals. When disabled, the quiescent

current is typically 375

µA, and the outputs are in a high impedance state.

IMP5

IMP52

© 2000 IMP, Inc.

Data Communications

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