FEATURES
• Complies with SCSI and SCSI-2
Standards
• 8pF Channel Capacitance during
Disconnect
• SCSI Plug and Play, Dual Low
Disconnect, Logic Low Command
Disconnects All Termination Lines
• Meets SCSI Hot Plugging Capability
• -650mA Sourcing Current for
Termination
• +200mA Sinking Current for Active
Negation
• 200µA Supply Current in Disconnect
Mode
• Trimmed Termination Current to 7%
• Trimmed Impedance to 7%
• Provides Active Termination for 18
Lines
UC5607
Plug and Play, 18-Line SCSI Active Terminator
BLOCK DIAGRAM
7/98
UDG-94124
Connect Connect Connect Disc
DISCNCT1
1010
DISCNCT2 0110
DESCRIPTION
The UC5607 provides 18 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 UC5607 provides a low disconnect feature which will disconnect all
terminating resistors, and will disable the regulator, greatly reducing
standby power. The output channels remain high impedance even without
Termpwr applied.
The UC5607 terminator is specially designed with two disconnect pins for
full SCSI Plug and Play (PnP) applications.
Custom power packages are utilized to allow normal operation at full
power conditions (2 Watts).
Internal circuit trimming is utilized, first to trim the impedance to a 7% tolerance, and then most importantly, to trim the output current to a 7% tolerance, as close to the max SCSI 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 28 pin wide body SOIC, and 28 pin PLCC, as well as 24 pin DIP.
Circuit Design Patented
2
UC5607
ABSOLUTE MAXIMUM RATINGS
Termpwr Voltage.................................+7V
Signal Line Voltage ..........................0Vto+7V
Regulator Output Current ...........................1A
Storage Temperature ...................-65°C to +150°C
Operating Temperature .................-55°C to +150°C
Lead Temperature (Soldering, 10 Sec.).............+300°C
Unless otherwise specified all voltages are with respect to
Ground. Currents are positive into, negative out of the specified
terminal. Consult Packaging Section of Unitrode Integrated Circuits databook for thermal limitations and considerations of
packages.
RECOMMENDED OPERATING CONDITIONS
Termpwr Voltage .........................3.8V to 5.25V
Signal Line Voltage ..........................0Vto+5V
Disconnect Input Voltage ..................0VtoTermpwr
CONNECTION DIAGRAMS
* QP package pins 12 - 18 serve as both heatsink and signal
ground.
** DISCNCT2
is internally tied to ground.
* DWP package pin 8 serves as signal ground; pins 7, 8, 9, 20,
21, 22 serve as heatsink/ground.
Note: Drawings are not to scale.
PLCC-28 (Top View)
QP Package
SOIC-28 (Top View)
DWP Package
DIL-24 (Top View)
NorJPackage
3
UC5607
Figure 1: Typical SCSI Bus Configuration Utilizing UC5607 Device
APPLICATION INFORMATION
UDG-98136
UNITRODE CORPORATION
7 CONTINENTAL BLVD. • MERRIMACK, NH 03054
TEL. (603) 424-2410FAX(603) 424-3460
ELECTRICAL CHARACTERISTICS Unless otherwise stated, these specifications apply for T
A
= 0°C to 70°C.
TRMPWR = 4.75V, DISCNCT1 = DISCNCT2 = 2.2V. TA=TJ.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
S
Supply Current Section
Termpwr Supply Current All termination lines = Open 30 45 mA
All termination lines = 0.5V 420 470 mA
Power Down Mode DISCNCT1
= DISCNCT2 = 0V 300 500
m
A
Output Section (Terminator Lines)
Terminator Impedance
D
I
LINE
= –5mA to –15mA TJ= 25°C 102 110 118 Ohms
0°C<TJ< 70°C 97 110 129 Ohms
Output High Voltage V
TRMPWR
= 4V (Note 1) TJ=25°C 2.6 2.9 3.1 V
0°C<T
J
< 70°C 2.55 2.9 3.2 V
Max Output Current V
LINE
= 0.5V TJ= 25°C –19.5 –21.9 –22.4 mA
0°C<TJ< 70°C –18.5 –21.9 –22.4 mA
Max Output Current V
LINE
= 0.5V, TRMPWR = 4V (Note 1) TJ= 25°C –18.0 –21.9 –22.4 mA
0°C<TJ< 70°C –17.0 –21.9 –22.4 mA
Output Leakage DISCNCT1 = DISCNCT2 = 0V, TRMPWR = 0V to 5.25V 10 400 nA
Output Capacitance DISCNCT1
= DISCNCT2 = 0V (Note 2) 8 10 pF
Regulator Section
Regulator Output Voltage All Termination Lines = 5V TJ = 25°C 2.7 2.9 3.1 V
0°C<T
J
< 70°C 2.55 2.9 3.2 V
Line Regulation TRMPWR = 4V to 6V 10 20 mV
Load Regulation I
REG
= +100mA to –100mA 20 50 mV
Note 1: Measuring each termination line while other 17 are low (0.5V).
Note 2: Guaranteed by design. Not 100% tested in production.
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any product or service without notice, and advise customers to obtain the latest version of relevant information
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accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
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performed, except those mandated by government requirements.
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DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL
APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR
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BE FULLY AT THE CUSTOMER’S RISK.
In order to minimize risks associated with the customer’s applications, adequate design and operating
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Copyright 1999, Texas Instruments Incorporated
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