Complies with SCSI, SCSI-2
Standards
9pF Channel Capacitance during
Disconnect
100
A Supply Current in
Disconnect Mode
Meets SCSI Hot Plugging Capability
-
300mA Sourcing Current for
Termination
+40mA Sinking Current for Active
Negation
Logic Command Disconnects all
Termination Lines
Trimmed Termination Current to 7%
Trimmed Impedance to 7%
Current Limit and Thermal
Shutdown Protection
The UC5604 provides 9 lines of active termination for a SCSI (Small Com-
puter Systems Interface) parallel bus. The SCSI standard recommends ac-
tive termination at both ends of the cable segment.
The UC5604 provides a disconnect feature which, when opened or driven
high, will disconnect all terminating resistors and disable the regulator,
greatly reducing standby power. The output channels remain high imped-
ance even without Termpwr applied.
The UC5604 is pin-for-pin compatible with its predecessor, the UC5603 - 9
line Active Terminator. The only functional difference between the UC5604
and UC5603 is the absence of the negative clamps. Parametrically, the
UC5604 has a 7% tolerance on impedance and current compared to a 3%
tolerance on the UC5603 and the sink current is reduced from 300mA to
40mA. Custom power packages are utilized to allow normal operation at
full power conditions (1.2 watts).
Internal circuit trimming is utilized, first to trim the impedance to a 7% toler-
ance, and then most importantly, to trim the output current to a 7% toler-
ance, 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 16 pin narrow body SOIC, 16 pin ZIP (zig-zag in line package)
and 24 pin TSSOP.
UC5604
9-Line Low Capacitance SCSI Active Terminator
FEATURES DESCRIPTION
BLOCK DIAGRAM
Circuit Design Patented
3/97
UDG-94064
ABSOLUTE MAXIMUM RATINGS
Termpwr Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +7V
Signal Line Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +7V
Regulator Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5A
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
-
65C to +150C
Operating Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
-
55C to +150C
Lead Temperature (Soldering, 10 Sec.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +300C
RECOMMENDED OPERATING CONDITIONS
Termpwr Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.8V to 5.25V
Signal Line Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +5V
Disconnect Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to Termpwr
CONNECTION DIAGRAMS
DIL-16 (Top View)
N or J Package
UC5604
* DP package pin 5 serves as signal ground; pins 4, 12, 13
serve as heatsink/ground.
* PWP package pin 5 serves as signal ground; pins 6, 7, 8, 9,
17, 18, 19, and 20 serve as heatsink/ground.
ZIP-16 (Top View)
Z Package
SOIC-16 (Top View)
DP Package
TSSOP-24 (Top View)
PWP Package
Note: Drawings are not to scale.
Unless otherwise specified all voltages are with respect to Ground. Currents are posi-
tive into, negative out of the specified terminal.
Consult Packaging Section of Unitrode Integrated Circuits databook for thermal limita-
tions and considerations of packages.
2
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Supply Current Section
Termpwr Supply Current
All termination lines = Open
14
20
mA
All termination lines = 0.5V
200
220
mA
Power Down Mode
DISCNCT = Open
100
150
A
Output Section (Terminator Lines)
Terminator Impedance
I
LINE
= -5mA to -15mA
97
110
129
Ohms
Output High Voltage
TRMPWR = 4V (Note 1)
0
C < T
J
< 70
C
2.55
3.2
V
T
J
= 25
C
2.6
2.9
3.1
V
Max Output Current
V
LINE
= 0.5V
T
J
= 25
C
-19.5
-21.9
-22.4
mA
0
C < T
J
< 70
C
-18.5
-21.9
-22.4
mA
Max Output Current
V
LINE
= 0.5V, TRMPWR = 4V (Note 1)
T
J
= 25
C
-18.0
-21.9
-22.4
mA
0
C < T
J
< 70
C
-17.0
-21.9
-22.4
mA
Output Clamp Level
I
LINE
= -30mA
-0.2
-0.05
0.1
V
Output Leakage
DISCNCT = 4V TRMPWR = 0V to 5.25V
REG = 0V
V
LINE
= 0 to 4V
10
400
nA
V
LINE
= 5.25V
100
A
TRMPWR = 0V to 5.25V, REG = Open
V
LINE
= 0V to 5.25V
10
400
nA
Output Capacitance
DISCNCT = Open (Note 2)
9
12
pF
Regulator Section
Regulator Output Voltage
2.5
2.9
3.2
V
Regulator Output Voltage
All Termination Lines = 5V
2.55
2.9
3.1
V
Line Regulation
TRMPWR = 4V to 6V
10
20
mV
Load Regulation
I
REG
= +100mA to -100mA
20
50
mV
Drop Out Voltage
All Termination Lines = 0.5V
1.0
1.2
V
Short Circuit Current
V
REG
= 0V
-200
-400
-600
mA
Sinking Current Capability
V
REG
= 3.5V
20
40
mA
Thermal Shutdown
170
C
Thermal Shutdown Hysteresis
10
C
Disconnect Section
Disconnect Threshold
1.1
1.4
1.7
V
Threshold Hysteresis
100
mV
Input Current
DISCNCT = 0V
150
200
A
ELECTRICAL CHARACTERISTICS
Unless otherwise stated, these specifications apply for T
A
= 0C to 70C.
TRMPWR = 4.75V, DISCNCT = 0V. T
A
= T
J
.
UC5604
Note 1: Measuring each termination line while other 8 are low (0.5V).
Note 2: Guaranteed by design. Not 100% tested in production.
Figure 1: Typical SCSI Bus Configurations Utilizing 2 UC5604 Devices
APPLICATION INFORMATION
UDG-94065
3
Figure 2: Typical Wide SCSI Bus Configurations Utilizing 3 UC5604 Devices.
UC5604
UDG-94066
UNITRODE CORPORATION
7 CONTINENTAL BLVD.
MERRIMACK, NH 03054
TEL. (603) 424-2410
FAX (603) 424-3460
APPLICATION INFORMATION (cont.)
4
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