
1A, 4.5V to 40V Input Buck Converters with
50mA Auxiliary LDO Regulators
Typical Operating Characteristics (continued)
(V IN_SW = V IN_LDO = V DRAIN =14V, V EN_SYS = V EN_SW = 2.4V, V REG = V DVREG , V SYNC = V SET_LDO = V SGND = V PGND = 0V, C REG =
1μF, C IN_SW = 0.1μF, C IN_LDO = 0.1μF, C LDO_OUT = 10μF, C DRAIN = 0.22μF, see Figures 6 and 7, T A = +25°C, unless otherwise noted.)
TURN-ON/-OFF WAVEFORM
TURN-ON/-OFF WAVEFORM
INCREASING V IN
MAX15014 toc10
INCREASING V IN
MAX15014 toc11
3.40
OUTPUT VOLTAGE vs. TEMPERATURE
I LOAD = 1A
I LOAD = 100m A
V IN
3.38
3.36
V IN
5V/div
5V/div
3.34
3.32
0V
0V
3.30
I LOAD = 0A
3.28
V OUT
2V/div
V OUT
2V/div
3.26
3.24
0V
0V
3.22
I LOAD = 1A
3.20
10ms/div
10ms/div
-40
-15
10 35 60 85
110
135
TEMPERATURE ( ° C)
EFFICIENCY vs. LOAD CURRENT
EFFICIENCY vs. LOAD CURRENT
EFFICIENCY vs. LOAD CURRENT
(MAX15015A)
(MAX15014)
100
90
80
V OUT = 3.3V
V IN = 4.5V
V IN = 7.5V
100
90
80
V OUT = 3.3V
V IN = 4.5V
V IN = 7.5V
100
90
80
V OUT = 5V
V IN = 7.5V
70
70
70
60
50
40
30
20
10
V IN = 12V
V IN = 24V
V IN = 40V
MAX15016A
I LDO_OUT = 0A
60
50
40
30
20
10
V IN = 12V
V IN = 24V
V IN = 40V
60
50
40
30
20
10
V IN = 24V
V IN = 12V
V IN = 40V
0
0
0
1
10 100
1000
1
10
100
1000
1
10 100
1000
LOAD CURRENT (mA)
EFFICIENCY vs. LOAD CURRENT
(MAX15017A)
LOAD CURRENT (mA)
LOAD-TRANSIENT RESPONSE
LOAD CURRENT (mA)
LOAD-TRANSIENT RESPONSE
100
90
80
V OUT = 5V
V IN = 7.5V
V IN = 12V, I OUT = 0.25A TO 1A
MAX15015A
MAX15014 toc17
V OUT
AC-COUPLED
V IN = 4.5V, I OUT = 0.25A TO 1A
MAX15015A
MAX15014 toc18
V OUT
AC-COUPLED
70
60
50
40
V IN = 24V
V IN = 12V
100mV/div
100mV/div
30
20
V IN = 40V
I LOAD
500mA/div
I LOAD
10
0
0
0
500mA/div
1
10 100
1000
200 μ s/div
200 μ s/div
LOAD CURRENT (mA)
8
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