Texas Instruments UCC5606PWPTR, UCC5606PWP, UCC5606N, UCC5606J, UCC5606DPTR Datasheet

The UCC5606 provides 9 lines of active termination for a SCSI (Small
Computer Systems Interface) parallel bus. The SCSI standard recom­mends active termination at both ends of the cable segment.

The UCC5606 is ideal for high performance 3.3V SCSI systems. The key
features contributing to such low operating voltage are the 0.1V drop out
regulator and the 2.7V reference. The reduced reference voltage was
necessary to accommodate the lower termi nation current dictated in the
SCSI-3 specification. During disconnect the supply current is typically
only 1µA, which makes the IC attractive for batt ery powered syst ems.

The UCC5606 is designed with an ultra low channel capacitance of

1.8pF, which eliminates effects on signal integri ty from disconnected ter­minators at interim points on the bus.

The UCC5606 can be programmed for either a 110 ohm or 2.5k ohm ter­mination. The 110 ohm termination is used for standard SCSI bus lengths
and the 2.5k ohm terminati on is typically used in short bus applications.
When driving the TTL compatible

DISCNCT pin directly, the 110 ohm ter-

mination is connected when the

DISCNCT pin is driven high, and discon-

nected when low. When the

DISCNCT pin is driven through an
impedance between 80k and 150k, the 2.5k ohm termination is con­nected when the

DISCNCT pin is driven h igh, and disconnected when

driven low.

UCC5606

9-Line 3-5 Volt SCSI Active Terminator, Reverse Disconnect

FEATURES DESCRIPTION

BLOCK DIAGRAM

Circuit Design Patented

• Complies with SCSI, SCSI-2 and
SCSI-3 Standards

• 2.7V to 7V Operation

• 1.8pF Channel Capacitance during

Disconnect

• 1µA Supply Current in Disconnect
Mode

• 110 Ohm/2.5k Programmable
Termination

• Completely Meets SCSI Hot Plugging

• -400mA Sourcing Current for

Termination

• +400mA Sinking Current for Active
Negation Drivers

• Trimmed Termination Current to 4 %

• Trimmed Impedance to 7%

• Current Limit and Thermal Shutdown

Protectio n

continue d

5/95

UDG-94067-1

UCC5606

The power amplifier output stage allows the UCC5606 to
source full termination current and sink active negation
current when all termination lines are actively negated.

The UCC5606 is pin for pin compatible with Unitrode’s
other 9 line SCSI terminators, except that

DISCNCT is
now active low, allowing lower capacitance and lower
voltage upgrades to existing systems. The UCC5606, as
with all Uni trode terminators, is completely hot pluggable
and appears as high imped ance at the terminating chan­nels with V

TRMPWR = 0V or open.

Internal circuit trimming is utilized, first to trim the 110
ohm termination impeda nce to a 7% tole rance, and then
most importantly, to trim the output current to a 4% toler­ance, as close to the max SCSI-3 spec as possible,
which maximizes noise margin in fast SCSI operation.

Other features include thermal shutdown and current
limit.

This device is offered in low thermal resistance versions
of the industry standard 16 pin narrow body SOIC, 16 pin
ZIP (Zig-Zag In Line package), 24 pin TSSOP and 28 pin
PLCC.

ABSOLUTE MAXIMUM RATINGS

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

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

Regulator Output Curren t. . . . . . . . . . . . . . . . . . . . . . . . . . 0.6A

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

Operating Tem pe ratur e . . . . . . . . . . . . . . . . . −−55°C to +150°C

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

RECOMMENDED OPERATING CONDITIONS

Termpwr Voltage . . . . . . . . . . . . . . . . . . . . . . . . . 2 .7 V to 5.25 V

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

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

Description Continued

Unless otherwise specified all volta ges ar e with respect to
Ground. Cur rents are positive into, negative out of the speci­fied terminal.
Consult Packaging Sectio n of Unitr ode Int egr at ed Circ uits dat­abook for thermal limitations and con sider at ions of pack ages .

CONNECTION DIAG RAMS

SOIC-16 (Top View)
DP Package

TSSOP-24 (Top View)
PWP Package

* DP package pin 5 ser ves as signal ground; pins 4, 12, 13
serve as heatsink/ground.

* PWP packa ge pin 5 serves as signal ground ; pins 6, 7, 8, 9,
17, 18, 19, and 20 ser ve as heat sink/ gr oun d.

ZIP-16 (Top View)
Z Package

Note: Drawings are not to scale.

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