UCC5618

最低电容的 18 线路 3-5V SE 端接器，用于 SCSI 至具有反向传感反向断开功能的 Ultra SCSI

The provides 18 lines of active termination for a SCSI Small Computers Systems Interface parallel bus. The SCSI standard recommends and Fast–20 Ultra requires active termination at both ends of the cable.

Pin for pin compatible with the UC5601 and UC5608, the UCC5618 is ideal for high performance 5V SCSI systems, Termpwr 4.0–5.25V. During disconnect the supply current is only 50µA typical, which makes the IC attractive for lower powered systems.

The UCC5618 is designed with a low channel capacitance of 2pF, which eliminates effects on signal integrity from disconnected terminators at interim points on the bus.

The power amplifier output stage allows the UCC5618 to source full termination current and sink active negation current when all termination lines are actively negated.

The UCC5618, as with all Unitrode terminators, is completely hot pluggable and appears as high impedance at the terminating channels with TRMPWR=0V or open.

Internal circuit trimming is utilized, first to trim the 110 impedance, and then most importantly, to trim the output current as close to the max SCSI–3 spec as possible, which maximizes noise margin in fast SCSI operation.

This device is offered in low thermal resistance versions of the industry standard 28 pin wide body SOIC, TSSOP and PLCC.

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Complies with SCSI, SCSI–2, SCSI–3, SPI and FAST–20 Standards

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2pF Channel Capacitance During Disconnect

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50µA Supply Current in Disconnect Mode

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110 Termination

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SCSI Hot Plugging Compliant, 10nA Typical

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+400mA Sinking Current for Active Negation

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–650mA Sourcing Current for Termination

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Trimmed Impedance to 5%

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Thermal Shutdown

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Current Limit