Texas Instruments UCC5618QPTR, UCC5618QP, UCC5618PWPTR, UCC5618PWP, UCC5618DWPTR Datasheet

UCC5618

DESCRIPTION

The UCC5618 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 UC5601 and UC5608, the UCC5618 is ideal
for high performance 5V SCSI systems, Termpwr 4.0-5.25V. During discon­nect the supply current is only 50µA typical, which makes the IC attractive
for lower powered systems.

The UCC5618 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 UCC5618 to source full termi­nation current and sink active negation current when all termination lines
are actively negated.

The UCC5618, 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 max
SCSI-3 spec as possible, which maximizes noise margin in fast SCSI op­eration.

This device is offered in low thermal resistance versions of the industry
standard 28 pin wide body SOIC, TSSOP and PLCC.

18-Line SCSI Terminator

FEATURES

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

• 2pF Channel Capacitance During
Disconnect

• 50µA Supply Current in Disconnect
Mode

• 110Ω Termination

• SCSI Hot Plugging Compliant, 10nA

Typical

• +400mA Sinking Current for Active
Negation

• –650mA Sourcing Current for
Termination

• Trimmed Impedance to 5%

• Thermal Shutdown

• Current Limit

6/98

BLOCK DIAGRAM

UDG-96005-1

Patented Circuit Design

2

UCC5618

PLCC-28 (Top View)
QP Package

ABSOLUTE MAXIMUM RATINGS

TEMPWR.......................................+7V

Signal Line Voltage ..........................0Vto+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

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

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

TSSOP-28 (Top View)
PWP Package

Note: Drawings are not to scale.

DIL-24 (Top View)
N Package

* 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

3

UCC5618

ELECTRICAL CHARACTERISTICS:

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

TRMPWR = 4.75V, DISCNCT = 0V, 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 420 440 mA

Power Down Mode DISCNCT = TRMPWR 50 100

µA

Output Section (Termination Lines)

Termination Impedance See Figure 1 104.5 110 115.5

Ω

Output High Voltage V

TRMPWR

= 4V (Note 1) 2.6 2.8 3 V

Max Output Current V

LINE

= 0.2V, TJ= 25°C –22.1 –23.3 –24 mA

V

LINE

= 0.2V –20.7 –23.3 –24 mA

V

LINE

= 0.2V, TERMPWR = 4V, TJ= 25°C

(Note 1)

–21 –23.3 –24 mA

V

LINE

= 0.2V, TRMPWR = 4V (Note 1) –20 –23 –24 mA

V

LINE

= 0.5V –22.4 mA

Output Leakage DISCNCT = 2.4V, TRMPWR = 0V to 5.25V,

REG = 0.2V, V

LINE

= 5.25V

10 400 nA

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 V

REG

= 0V –475 –650 –950 mA

Sinking Current Capability V

REG

= 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.

Figure 1. Termline Impedance Measurement Circuit

Procedure:

1) Measure V

REG

N.L.

2) Set V

L

= 0.2V

3) Measure I

MAX

at 0.2V

4) Impedance =

VNL V

I

REG

MAX

...02

UDG-96102-1

4

UCC5618

PIN DESCRIPTIONS

DISCNCT: Taking this pin high or leaving it open causes

the 18 channels to become high impedance and the chip
to go into low-power mode; a low state allows the
channels to provide normal termination.

GND: Ground reference for the IC.

LINE1–LINE18: 110Ω termination channels.
REG: Output of the internal 2.8V regulator.
TRMPWR: Power for the IC.

APPLICATION INFORMATION

UDG-96012-1

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

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