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DCT104803
DCT104805
SLVS407 – OCTOBER 2001
7
www.ti.com
APPLICATION INFORMATION
remote sensing
Full-differential remote sensing can be achieved by connecting V(sense) (see Figure 1 schematic) and 0V(sense)
at the point of load. The maximum terminal voltage should not exceed the defined output voltage trim range
values. Care should be taken when laying out the sense connections to avoid noise pickup. If wire is used for
sense leads, it is recommended that it be formed into a twisted pair. Additional noise suppression can be
provided by adding 0.1-
F ceramic capacitors between each of the output pins and the corresponding sense
connection.
Protection can be added in the event of one of the remote sense leads breaking by inserting 50-
resistors
between V(sense) and VO and 0 V(sense) and 0 VO. These protection resistors should be connected locally to VO
and 0 VO.
If remote sensing is not required, V(sense) and 0 V(sense) should be connected locally to VO and 0 VOrespectively.
safety
For safety agency approval of the end-system in which the DCT10408x is used, the unit must be installed in
compliance with the safety and separation requirements of the end-use safety standard: UL 1950, CSA 22.2
and EN 60 950.
The isolation system deployed in the DCT10408x is considered to be basic insulation in accordance with UL
1950, CSA 22.2 and EN 60 950. The following circuits can be connected together:
BETWEEN (INPUT)
AND (OUTPUT)
TNV-2 Circuit
TNV-3 Circuit
Unearthed SELV circuit
Earthed SELV circuit
Earthed or unearthed
Hazardous voltage
Secondary circuit
Earthed SELV circuit
ELV Circuit
Unearthed hazardous voltage
Secondary circuit
In order to maintain basic insulation between the above circuits, special consideration must be given to the
layout of the host application printed-circuit board. It is assumed that the application installation is category II
and the comparative tracking index is IIIa + IIIb.
Creepage/clearance distances must be adhered to between the various pin/tracking connections as shown in
the following table:
Between pins
And pins
Creepage (minimum)
Clearance (minimum)
1 to 8 and 25–28
10 to 21
1,3 mm
0,7 mm
To ensure there are no operational issues, the following creepage/clearance distances should be adhered to:
Between pin
And pin
Creepage (minimum)
Clearance (minimum)
VI (3)
0V(dev) (2), PWMa (1), DNC (4)
1,3 mm
0,7 mm
DNC (21)
0V(dev) (26)
1,2 mm
0,7 mm
The input to the DCT10, should be protected by a 5-A slow-blow fuse.
PR
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DU
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PREVIEW