Texas Instruments UCC5617DWPTR, UCC5617DWP Datasheet

18-Line SCSI Terminator (Reverse Disconnect)

UCC5617

FEATURES

• Complies with SCSI, SCSI-2,
SCSI-3 and FAST-20 Standards

• 2pF Channel Capacitance
During Disconnect

•50µA Supply Current in
Disconnect Mode

• 110Ω Termination

• SCSI Hot Plugging Compliant,
10nA T ypical

• +400mA Sinking Current for
Active Negation

• −650mA Sourcing Current for
Termination

• Trimmed Impedance to 5%

DESCRIPTION

The UCC5617 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 UC5609, the UCC5617 is ideal for high perfor­mance 5V SCSI systems, Termpwr 4.0V to 5.25V.During disconnect the sup­ply current is only 50µA typical, which makes the IC attractive for lower pow­ered systems.

The UCC5617 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 UCC5617 to source full termina­tion current and sink active negation current when all termination lines are
actively negated.

The UCC5617, 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 110Ω impedance, and then
most importantly, to trim the output current as close to the maximum SCSI-3
specification 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 stan-

dard 28 pin wide body SOIC, TSSOP and PLCC.

4/97

BLOCK DIAGRAM

UDG-96073

Circuit Design Patented

2

UCC5617

ABSOLUTE MAXIMUM RATINGS

Tempwr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+7V

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

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

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

Operating Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . .−55°C to +150°C

Lead Temperature (Soldering, 10 Seconds) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .300°C

All currents are positive into, negative out of the specified terminal.Consult Packaging
Section of Databook for thermal limitations and considerations of packages.

CONNECTION DIAGRAMS

PLCC-28 (Top View)
QP Package

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

SOIC-28 (Top View)
DWP Package

DIL-24 (Top View)
N Package

* N package for engineering samples only.

* 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.

TSSOP-28 (Top View)
PWP Package

* PWP package pin 23 serves as signal ground;pins 7, 8, 9,
20, 21, and 22 serve as heatsink ground.

3

UCC5617

ELECTRICAL CHARACTERISTICS

Unless otherwise stated these specifications apply for TA = 0°C to 70°C,

TRMPWR = 4.75V, DISCNCT = 4.75V, TA = TJ.

PARAMETER TEST CONDITIONS MIN TYP MAX UNITS

Supply Current Section

Termpwr Supply Current All termination lines = Open 1 2 mA

All termination lines = 0.2V 420 450 mA

Power Down Mode DISCNCT = 0V 50 100 µA

Output Section (Termination Lines)

Termination Impedance (Note 3) 104.5 110 115.5 Ω
Output High Voltage VTRMPWR = 4V (Note 1) 2.6 2.8 3 V
Maximum Output Current VLINE = 0.2V, TJ = 25°C −22.1 −23.3 −24 mA

VLINE = 0.2V −20.7 −23.3 −24 mA
VLINE = 0.2V, TRMPWR = 4V, TJ = 25°C (Note 1) –21 –23 –24 mA
VLINE = 0.2V, TRMPWR = 4V (Note 1) –20 –23 –24 mA
VLINE = 0.5V −22.4 mA

Output Leakage DISCNCT = 0V, TRMPWR =0V to 5.25V, 10 400 nA

REG = 0.2V, VLINE = 5.25V

Output Capacitance DISCNCT = 2.4V (Note 2) 2 3.5 pF

Regulator Section

Regulator Output Voltage 2.6 2.8 3 V
Drop Out Voltage All Termination Lines = 0.2V 0.4 0.8 V
Short Circuit Current VREG = 0V –475 −650 −850 mA
Sinking Current Capability VREG = 3.5V 200 400 800 mA
Thermal Shutdown 170 °C
Thermal Shutdown Hysteresis 10 °C

Disconnect Section

Disconnect Threshold 0.8 1.5 2 V
Input Current DISCNCT = 0V −10 −30 µA

Note 1:Measuring each termination line while other 17 are low (0.2V).
Note 2:Guaranteed by design.Not 100% tested in production.
Note 3:Tested by measuring I

OUT

with V

OUT

= 0.2V and V

OUT

with no load, then calculating:

Z =

.

VOUT N.L.– 0.2V

IOUT at 0.2V

Procedure:

1) Measure VREG N.L.

2) Set VL = 0.2V;Measure I

MAX at 0.2V

3) Impedance =

VREG N.L.– 0.2V

IMAX at 0.2V

Figure 1.Termline Impedance Measurement Circuit

UDG-97108

4

UCC5617

DISCNCT: T aking this pin low causes the 18 channels to

become high impedance and the chip to go into low-power
mode;a high or open state allows the channels to provide
normal termination.

GND: Ground reference for the IC.

LINE 1-18: 110Ω termination channels.
REG: Output of the internal 2.8V regulator.
TRMPWR:Power for the IC .

PIN DESCRIPTIONS

UNITRODE CORPORATION
7 CONTINENTAL BLVD.• MERRIMACK, NH 03054
TEL.[phone] • FAX [phone]

APPLICATION INFORMATION

UDG-96074

IMPORTANT NOTICE

T exas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue
any product or service without notice, and advise customers to obtain the latest version of relevant information
to verify, before placing orders, that information being relied on is current and complete. All products are sold
subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those
pertaining to warranty, patent infringement, and limitation of liability.

TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily
performed, except those mandated by government requirements.

CERT AIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF
DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL
APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR
WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER
CRITICAL APPLICATIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICA TIONS IS UNDERSTOOD T O
BE FULLY AT THE CUSTOMER’S RISK.

In order to minimize risks associated with the customer’s applications, adequate design and operating
safeguards must be provided by the customer to minimize inherent or procedural hazards.

TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent
that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other
intellectual property right of TI covering or relating to any combination, machine, or process in which such
semiconductor products or services might be or are used. TI’s publication of information regarding any third
party’s products or services does not constitute TI’s approval, warranty or endorsement thereof.

Copyright  1999, Texas Instruments Incorporated