Texas Instruments UC5601QPTR, UC5601QP, UC5601N, UC5601DWPTR, UC5601DWP Datasheet

SCSI Active Terminator

FEATURES

∙Complies with SCSI, SCSI-2 Standards

∙10pF Channel Capacitance During Disconnect

∙Active Termination for 18 Lines

∙Logic Command Disconnects all Termination Lines

∙Low Supply Current in Disconnect Mode

∙Trimmed Regulator for Accurate Termination Current

∙Current Limit and Thermal Shutdown Protection

∙110 Ohm Termination

∙Meets SCSI Hot Plugging

UC5601

DESCRIPTION

The UC5601 provides precision resistive pull-up to a 2.9V reference for all 18 lines in a Small Computer Systems Interface (SCSI) bus cable. The SCSI-2 standard recommends active termination at both ends of every cable segment utilizing single ended drivers and receivers.

Internal circuit trimming is utilized, first to reduce resistor tolerances to ±3% and then to adjust the regulator’s output voltage to insure termination current accuracy of ±3%.

The UC5601 provides a disconnect feature which, upon a logic command, disconnects all terminating resistors, and turns off the regulator; greatly reducing standby power.

Other features include negative clamping on all signal lines, 20mA of active negation sink current capability, regulator current limiting, and thermal shutdown protection.

This device is offered in low thermal resistance versions of the industry standard 28 pin wide body SOIC and PLCC, as well as a 24 pin DIL plastic package.

BLOCK DIAGRAM

UDG-94060

Circuit Design Patented

10/94

ABSOLUTE MAXIMUM RATINGS

Termpwr Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +7V Signal Line Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +7V Regulator Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1A Storage Temperature . . . . . . . . . . . . . . . . . . . −65°C to +150°C Operating Temperature . . . . . . . . . . . . . . . . . −55°C to +150°C Lead Temperature (Soldering, 10 Sec.) . . . . . . . . . . . . . +300°C

Unless otherwise specified all voltages are with respect to Ground. Currents are positive into, negative out of the specified terminal.

Consult Packaging Section of Unitrode Integrated Circuits databook for thermal limitations and considerations of packages.

RECOMMENDED OPERATING CONDITIONS

Termpwr Voltage . . . . . . . . . . . . . . . . . . . . . . . . . 4.0V to 5.25V Signal Line Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +3V Disconnect Input Voltage . . . . . . . . . . . . . . . . . . 0V to Termpwr

UC5601

CONNECTION DIAGRAMS

PLCC-28 (Top View)

QP Package

* QP package pins 12 - 18 serve as both heatsink and signal ground.

SOIC-28 (Top View)

DIL-24 (Top View)

DWP Package

N or J Package

* DWP package pin 28 serves as signal ground; pins 7, 8, 9, 20, 21, 22 serve as heatsink/ground.

Note: Drawings are not to scale.

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