UCC5620
27-Line SCSI Terminator
FEATURES
•Complies with SCSI, SCSI-2, SCSI-3, SPI and FAST-20 (Ultra) Standards
•2.5pF Channel Capacitance during Disconnect
•100mA Supply Current in Disconnect Mode
•4V To 7V Operation
• 110 Termination
•Completely Meets SCSI Hot Plugging
•–900mA Sourcing Current for Termination
•+500mA Sinking Current for Active Negation
•Logic Command Disconnects all Termination Lines
•Trimmed Impedance to 5%
•Current Limit and Thermal Shutdown Protection
DESCRIPTION
UCC5620 provides 27 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.
The UCC5620 is ideal for high performance 5V SCSI systems. During disconnect the supply current is typically only 100µ A, which makes the IC attractive for lower powered systems.
The UCC5620 is designed with a low channel capacitance of 2.5pF, which eliminates effects on signal integrity from disconnected terminators at interim points on the bus.
The power amplifier output stage allows the UCC5620 to source full termination current and sink active negation current when all termination lines are actively negated.
The UCC5620, as with all Unitrode terminators, is completely hot pluggable and appears as high impedance at the teminating channels with VTRMPWR = 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 standard 36-Pin Wide Body QSOP (MWP) and 48-Pin LQFP (FQP).
Consult QSOP-36 or LQFP-48 packaging diagram for exact dimensions.
BLOCK DIAGRAM
Circuit Design Patented
SLUS287A - OCTOBER 1999
UDG-96109
ABSOLUTE MAXIMUM RATINGS
Termpwr Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +7V Signal Line Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +7V Regulator Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5A Storage Temperature . . . . . . . . . . . . . . . . . . . − 65
C to +150
C Junction Temperature . . . . . . . . . . . . . . . . . . . − 55
C to +150
C Lead Temperature (Soldering, 10 Sec.). . . . . . . . . . . . . +300
C
Currents are positive into, negative out of the specified terminal. Consult Packaging Section of Databook for thermal limitations and considerations of packages.
LFQP-48 (Top View) |
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FQP Package |
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HS/GND |
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HS/GND |
HS/GND |
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LINE 8 |
LINE 9 |
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LINE 7 |
LINE 23 |
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LINE 6 |
LINE 24 |
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LINE 5 |
N/C |
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LINE 22 |
N/C |
48 |
47 |
46 |
45 |
44 |
43 |
42 |
41 |
40 |
39 |
38 |
37 |
LINE 21 |
1 |
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36 |
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LINE 25 |
2 |
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35 |
LINE 20 |
LINE 26 |
3 |
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34 |
LINE 19 |
LINE 27 |
4 |
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33 |
REG |
HS/GND |
5 |
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32 |
HS/GND |
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HS/GND |
6 |
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31 |
HS/GND |
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HS/GND |
7 |
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30 |
HS/GND |
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HS/GND |
8 |
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29 |
HS/GND |
N/C |
9 |
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28 |
TRMPWR |
DISCNCT1 |
10 |
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27 |
LINE 18 |
LINE 10 |
11 |
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26 |
LINE 17 |
LINE 11 |
12 |
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25 |
LINE 16 |
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13 |
14 |
15 |
16 |
17 |
18 |
19 |
20 |
21 |
22 |
23 |
24 |
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N/C |
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LINE 15 |
LINE 12 |
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LINE 4 |
LINE 13 |
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LINE 3 |
LINE 14 |
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LINE 2 |
HS/GND |
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LINE 1 |
HS/GND |
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HS/GND |
UCC5620
CONNECTION DIAGRAM
SSOP-36 (Top View)
MWP Package
LINE8 |
1 |
36 |
LINE7 |
LINE9 |
2 |
35 |
LINE6 |
LINE23 |
3 |
34 |
LINE5 |
LINE24 |
4 |
33 |
LINE22 |
LINE25 |
5 |
32 |
LINE21 |
LINE26 |
6 |
31 |
LINE20 |
LINE27 |
7 |
30 |
LINE19 |
GND |
8 |
29 |
REG |
GND |
9 |
28 |
GND |
GND |
10 |
27 |
GND |
DISCNCT |
11 |
26 |
GND |
LINE10 |
12 |
25 |
TRMPWR |
LINE11 |
13 |
24 |
LINE18 |
LINE12 |
14 |
23 |
LINE17 |
LINE13 |
15 |
22 |
LINE16 |
LINE14 |
16 |
21 |
LINE15 |
LINE1 |
17 |
20 |
LINE4 |
LINE2 |
18 |
19 |
LINE3 |
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 |
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TRMPWR Supply Current |
All Termination Lines = Open |
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1 |
2 |
mA |
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All Termination Lines = 0.2V |
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630 |
650 |
mA |
Power Down Mode |
DISCNCT = TRMPWR |
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100 |
200 |
µ A |
2
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