ETC UC5608N

UC5608
18-Line Low Capacitance SCSI Active Terminator
FEATURES
DESCRIPTION
•
Complies with SCSI, SCSI-2 and SPI-2
Standards
•
6pF Channel Capacitance during
Disconnect
The UC5608 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 bus cable.
•
100µA Supply Current in Disconnect
Mode
•
Meets SCSI Hot Plugging Capability
•
−650mA Sourcing Current for
Termination
•
+200mA Sinking Current for Active
Negation
•
Provides Active Termination for 18 Lines
•
Logic Command Disconnects all
Termination Lines
•
Trimmed Termination Current to 5%
•
Trimmed Impedance to 5%
•
Current Limit and Thermal Shutdown
Protection
The UC5608 is pin-for-pin compatible with its predecessors, the
UC5601 and UC5602 - 18 Line Active Terminator. Parametrically the
UC5608 has a 5% tolerance on impedance and current compared to a
3% tolerance on the UC5601 and the sink current is increased from
20 to 200mA. The low side clamps have been removed. Custom
power packages are utilized to allow normal operation at full power
conditions (2 Watts).
When in disconnect mode the terminator will disconnect all terminating resistors and disable the regulator, greatly reducing standby
power. The output channels remain high impedance even without
Termpwr applied.
Internal circuit trimming is utilized to trim the impedance to a 5% tolerance and, most importantly, to trim the output current to a 5% tolerance, as close to the max SCSI spec as possible, which maximizes
noise margin in fast SCSI operation.
Other features include 4.0 to 5.25V Termpwr, thermal shutdown and
current limit.
This device is offered in low thermal resistance versions of the industry standard 28 pin wide body SOIC, 28 pin wide body TSSOP, and 28
pin PLCC, as well as 24 pin DIP.
BLOCK DIAGRAM
UDG-94047
Circuit Design Patented
3/97
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UC5608
ABSOLUTE MAXIMUM RATINGS
Termpwr Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +7V
Signal Line Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +5V
Disconnect Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to Termpwr
CONNECTION DIAGRAMS
PLCC-28 (Top View)
QP Package
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.
* QP package pins 12 - 18 serve as both heatsink and signal
ground.
DIL-24 (Top View)
N or J Package
SOIC-28 (Top View)
DWP Package
* DWP package pin 28 serves as signal ground; pins 7, 8, 9,
20, 21, 22 serve as heatsink/ground.
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Note: Drawings are not to scale.
2
UC5608
ELECTRICAL CHARACTERISTICS Unless otherwise stated, these specifications apply for TA = 0°C to 70°C. TRMPWR =
4.75V, DISCNCT = Ground. TA = TJ.
PARAMETER
Supply Current Section
Termpwr Supply Current
TEST CONDITIONS
MIN
All termination lines = Open
All termination lines = 0.5V
DISCNCT = Open
Power Down Mode
Output Section (Terminator Lines)
Terminator Impedance
∆ILINE = -5mA to -15mA
Output High Voltage
VTRMPWR = 4V (Note 1)
Max Output Current
VLINE = 0.5V
Max Output Current
Output Leakage
Output Capacitance
Regulator Section
Regulator Output Voltage
Regulator Output Voltage
Line Regulation
Drop Out Voltage
Short Circuit Current
Sinking Current Capability
Thermal Shutdown
Thermal Shutdown Hysteresis
Disconnect Section
Disconnect Threshold
104.5
2.65
TJ = 25°C
-20.3
0°C < TJ < 70°C -19.8
TJ = 25°C
-19.5
VLINE = 0.5V, TRMPWR = 4V (Note 1)
0°C < TJ < 70°C -19.0
0°C < TJ < 70°C -21.6
VLINE = 0.2V, TRMPWR = 4V to 5.25V
TRMPWR
=
0V
to
5.25V
V
LINE = 0 to 4V
DISCNCT = 4V
REG = 0V
VLINE = 5.25V
TRMPWR = 0V to 5.25V, REG = Open
VLINE = 0V to 5.25V
DISCNCT = Open (Note 2)
All Termination Lines = 4V
TRMPWR = 4V to 6V
All Termination Lines = 0.5V
VREG = 0V
VREG = 3.5V
2.8
2.8
-450
100
1.1
TYP
MAX
UNITS
17
400
100
25
430
150
mA
mA
µA
110
2.9
-21.5
-21.5
-21.5
-21.5
-24.0
10
10
115.5
3.0
-22.4
-22.4
-22.4
-22.4
-25.4
400
100
400
Ohms
V
mA
mA
mA
mA
mA
nA
µA
nA
6
7
pF
2.9
2.9
10
1.0
-650
200
170
10
3
3
20
1.2
-950
500
V
V
mV
V
mA
mA
°C
°C
1.4
1.7
V
Note 1: Measuring each termination line while other 17 are low (0.5V).
Note 2: Guaranteed by design. Not 100% tested in production.
APPLICATION INFORMATION
UDG-94048
Figure 1: Typical SCSI Bus Configuration
UNITRODE CORPORATION
7 CONTINENTAL BLVD. • MERRIMACK, NH 03054
TEL. (603) 424-2410 • FAX (603) 424-3460
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3
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