ADDC02803SC/ADDC02805SA
With regard to the range to which the output voltage can be
adjusted by the user, there are two concerns. As the output
voltage is raised it may become difficult to maintain regulation
at full power and low input voltage. As the output voltage is
lowered, it may become difficult to maintain regulation at mini-
mum power and high input line. In addition, if the output
voltage is reduced below 3 V, the secondary side control circuit
may not have a sufficient supply voltage to operate correctly.
1.0
0.8
0.6
0.4
0.2
Pin 4 (STATUS)
Pin 4 is active high referenced to –SENSE (Pin 1), indicating
that the output voltage is typically within ±5%. The pin is both
pulled up and down by internal circuitry. Figures 26, 27 and 28
show the typical source and sink capabilities of the status output.
Refer to the paragraphs describing Pin 3 (ADJUST) for effect
on status trip point.
0.0
1.0
4.0
7.0
10.0
– mA
13.0
16.0
19.0
I
OL
Figure 28. Sink Capability of Status Output
3.00
2.75
2.50
2.25
2.00
1.75
1.50
Pin 5 (VAUX
)
Pin 5 is referenced to the input return and provides a semi-
regulated 13 V to 15 V dc voltage supply for miscellaneous
system use. The maximum permissible current draw is 5 mA
and the voltage varies with the output load of the converter as
shown in Figures 29 and 30.
15.0
14.5
14.0
13.5
13.0
0.4
0.5
0.6
0.7
0.8
0.9
– mA
1.0
1.1
1.2
1.3
1.4
I
OH
Figure 26. Source Capability of Status Output
(ADDC02803SC)
4.2
3.8
3.4
3.0
0
2
4
6
8
10
12
14
16
18
20
22
OUTPUT CURRENT – A
Figure 29. VAUX vs. Converter Output Current
(ADDC02805SA)
14.0
13.5
13.0
2.6
2.2
0.8
1.0
1.2
1.4
1.6
OH
1.8
– mA
2.0
2.2
2.4
2.6
I
Figure 27. Source Capability of Status Output
(ADDC02805SA)
12.5
12.0
11.5
0
2
4
6
8
10
12
14
16
18
20
22
OUTPUT CURRENT – A
Figure 30. VAUX vs. Converter Output Current
(ADDC02803SC)
REV. A
–9–
ADI [ ADI ]
