UCC5630A
APPLICATION INFORMATION
TERMPWR
36 TERMPWR
CONTROL LINES
19 MSTR/SLV
17 DISCNCT
REG
1
DIFSENS 20
DIFFB
21
50k
4.7µF
.
50k
TERMPWR 36
CONTROL LINES
MSTR/SLV 19
20 DIFSENS
DIFF B
21
DISCNCT 17
REG
1
TERMPWR
4.7µF
.
4.7µF
.
4.7µF
36 TERMPWR
DATA LINES (9)
19 MSTR/SLV
4.7µF
.
17 DISCNCT
REG
1
NC 20
DIFF B
21
TERMPWR 36
DATA LINES (9)
MSTR/SLV 19
20 NC
DIFFB
21
DISCNCT 17
REG
1
4.7µF
.
4.7µF
.
4.7µF
36 TERMPWR
DATA LINES (9)
19 MSTR/SLV
17 DISCNCT
REG
1
NC 20
DIFFB
21
TERMPWR 36
DATA LINES (9)
MSTR/SLV 19
20 NC
DIFFB
21
DISCNCT 17
REG
1
4.7µF
.
4.7µF
UDG-98193
Figure 2. Application diagram.
All SCSI buses require a termination network at each
end to function properly. Specific termination require-
ments differ, depending on which types of SCSI devices
are present on the bus.
The UCC5630A is used in multi-mode active termination
applications, where single ended (SE) and low voltage
differential (LVD) devices might coexist. The UCC5630A
has both SE and LVD termination networks integrated
into a single monolithic component. The correct termina-
tion network is automatically determined by the SCSI bus
"DIFSENS" signal.
The SCSI bus DIFSENS signal line is used to identify
which types of SCSI devices are present on the bus. On
power-up, the UCC5630A DIFSENS drivers will try to de-
liver 1.3V to the DIFSENS line. If only LVD devices are
present, the DIFSENS line will be successfully driven to
1.3V and the terminators will configure for LVD operation.
If any single ended devices are present, they will present
a short to ground on the DIFSENS line, signaling the
UCC5630A(s) to configure into the SE mode, accommo-
dating the SE devices. Or, if any high voltage differential
(HVD) devices are present, the DIFSENS line is pulled
high and the terminator will enter a high impedance
state, effectively disconnecting from the bus.
5
TI [ TEXAS INSTRUMENTS ]
