Datasheet

LTC3419
14
3419fa
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 40mA TO 600mA
I
LOAD
500mA/DIV
I
L
500mA/DIV
V
OUT
100mV/DIV
AC-COUPLED
20μs/DIV
3419 F04c1
V
IN
= 3.6V
V
OUT
= 2.5V
I
LOAD
= 40mA TO 600mA
I
LOAD
500mA/DIV
I
L
500mA/DIV
V
OUT
100mV/DIV
AC-COUPLED
20μs/DIV
3419 F04c2
Using the same analysis for channel 2 (V
OUT2
= 1.8V),
the results are:
L2 = 1.9μH
R3 = 59k
R4 = 118k
C
F2
= 22pF
Figure 4 shows the complete schematic for this example,
along with the effi ciency curve and transient response.
Figure 4a. Design Example Circuit
Figure 4b. Effi ciency vs Output Current
Figure 4c. Transient Response
APPLICATIONS INFORMATION
V
IN
RUN2 RUN1
LTC3419
V
FB2
SW2
SW1
MODE
V
FB1
C
F2
, 22pF C
F1
, 22pF
GND
V
IN
2.5V TO 5.5V
V
OUT2
1.8V AT
600mA
V
OUT1
2.5V AT
600mA
3419 F04a
R4
118k
R2
187k
R3
59k
R1
59k
L2
2.2
μH
L1
2.2μH
C
OUT2
10μF
C
OUT1
10μF
C1
10
μF
C1, C2, C3: TAIYO YUDEN JMK316BJ106ML L1, L2: TDK VLF3010AT2R2M1RD
Load Step Transient Response
OUTPUT CURRENT (mA)
EFFICIENCY (%)
100
90
80
70
60
50
40
30
20
10
0
0.1 10 100 10001
V
OUT
= 1.8V
V
IN
= 2.7V
V
IN
= 3.6V
V
IN
= 4.2V
3419 F04b
OUTPUT CURRENT (mA)
EFFICIENCY (%)
100
90
80
70
60
50
40
30
20
10
0
0.1 10 100 10001
V
OUT
= 2.5V
V
IN
= 2.7V
V
IN
= 3.6V
V
IN
= 4.2V