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

UC5601

SCSI Active Terminator

FEATURES DESCRIPTION

• 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

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

• Trimmed Regulator for Accurate
Termination Current

• Current Limit and Thermal
Shutdown Protection

• 110 Ohm Termination

• Meets SCSI Hot Plugging

BLOCK DIAGRAM

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 re sistance versions of the industry
standard 28 pin wide body SOIC and PLCC, as well as a 24 pin DIL plastic
package.

10/94

UDG-94060

Circuit Design Patented

UC5601

ABSOLUTE MAXIMUM RATINGS

Termpwr Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +7V

Signal Line Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +7V

Regulator Output Current. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1A

Storage Temperature . . . . . . . . . . . . . . . . . . . −−65°C to +150°C

Operating Tem perat ure . . . . . . . . . . . . . . . . . −−55°C to +150°C

Lead Temperat ure (Solde ring, 10 Sec.). . . . . . . . . . . . . +300°C

Unless otherwise specified all volta ges are with respect to
Ground. Cur ren ts are po sitive into, negative out of the speci­fied terminal.
Consult Packaging Section of Unitr ode Int egr ated Circ uits dat­abook for thermal limitations and consider ations of pack ages .

RECOMMENDED OPERATING CONDITIONS

Termpwr Voltage . . . . . . . . . . . . . . . . . . . . . . . . . 4.0V to 5.25V

Signal Line Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +3V

Disconnect Input Voltage . . . . . . . . . . . . . . . . . . 0V to Te rmpwr

SOIC-28 (Top View)
DWP Package

CONNECTION DIAGRAMS

PLCC-28 (Top View)
QP Package

* QP package pins 12 - 18 serve as both hea tsink and sign al
ground.

DIL-24 (Top View)
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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