UCC5611

The power amplifier output stage allows the UCC5611 to

source full termination current and sink active negation

current when all termination lines are actively negated.

The UCC5611 is pin for pin compatible with Unitrode’s

other 18 line SCSI terminators, except that DISCNCT is

now active low, allowing lower capacitance and lower

voltage upgrades to existing systems. The UCC5611, as

with all Unitrode terminators, is completely hot pluggable

and appears as high impedance at the terminating chan-

Internal circuit trimming is utilized, first to trim the 110

ohm termination impedance to a 7% tolerance, and then

most importantly, to trim the output current to a 4% toler-

ance, as close to the max SCSI-3 spec as possible,

which maximizes noise margin in FAST-20 SCSI opera-

tion.

Other features include thermal shutdown and current

limit.

This device is offered in low thermal resistance versions

of the industry standard 28 pin wide body SOIC, 24 pin

wide body DIP and 28 pin PLCC.

ABSOLUTE MAXIMUM RATINGS

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

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

Regulator Output Current . . . . . . . . . . . . . . . . . . Self-regulating

Storage Temperature . . . . . . . . . . . . . . . . . . .

−65°C to +150°C

Operating Temperature . . . . . . . . . . . . . . . . .

−55°C to +150°C

Lead Temperature (Soldering, 10 Sec.) . . . . . . . . . . . . . +300°C

RECOMMENDED OPERATING CONDITIONS

Termpwr Voltage . . . . . . . . . . . . . . . . . . . . . . . . 2.75V to 5.25V

Signal Line Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +5V

Disconnect Input Voltage . . . . . . . . . . . . . . . . . . 0V to Termpwr

Description Continued

Unless otherwise specified all voltages are with respect to

Ground. Currents are positive into, negative out of the speci-

fied terminal.

Consult Packaging Section of Unitrode Integrated Circuits dat-

abook for thermal limitations and considerations of packages.

CONNECTION DIAGRAMS

PLCC-28 (Top View)

QP Package

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

ground.

* DWP package pin 28 serves as signal ground; pins 7, 8, 9,

20, 21, 22 serve as heatsink/ground.

SOIC-28 (Top View)

DWP Package

Note: Drawings are not to scale.

DIL-24 (Top View)

N or J Package

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