Owner manual

AP1539
18V 4A 300KHz BUCK CONVERTER
AP1539 Rev. 4 6 of 13 OCTOBER 2009
DS31477 www.diodes.com © Diodes Incorporated
Typical Performance Characteristics
V
IN
vs. Frequency
(V
OUT
= 3.3V, I
OUT
= 0.2A)
306
308
310
312
314
316
318
320
322
324
326
024681012141618
V
IN
(V)
F
OSC
(kHz)
V
IN
vs . V
FB
(V
OUT
= 3.3V, I
OUT
= 0.2A)
0.780
0.785
0.790
0.795
0.800
0.805
0.810
0.815
0.820
0 2 4 6 8 10 12 14 16 18
V
IN
(V)
V
FB
(V)
Line Regulation
(V
OUT
= 3.3V, I
OUT
= 0.2A)
3.00
3.05
3.10
3.15
3.20
3.25
3.30
3.35
3.40
024681012141618
V
IN
(V)
V
OUT
(V)
Load Regulation
(V
IN
= 12V)
3.25
3.26
3.27
3.28
3.29
3.30
3.31
3.32
3.33
3.34
3.35
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
I
OUT
(A)
V
OUT
(V)
Efficiency
(V
IN
= 12V)
0
10
20
30
40
50
60
70
80
90
100
0.0 1.0 2.0 3.0 4.0
I
OUT
(A)
Efficiency (%)
VOUT=3.3V
VOUT=5V
Switch Current Limit
(T
A
= 25
℃
)
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
0 2 4 6 8 10 12 14 16 18
V
IN
(V)
Current Limit (A)
ROCSET=6.8k
ROCSET=4.7k