Datasheet

25
LTC3704
3704fb
APPLICATIO S I FOR ATIO
WUUU
RUN
I
TH
NFB
FREQ
MODE/SYNC
SENSE
V
IN
INTV
CC
GATE
GND
LTC3704
R
T
80.6k
1%
C
VCC
4.7μF
X5R
M1
D1
•
L1*
L2*
C
OUT
100μF
X5R
V
IN
3V to 5V
V
OUT
–8.0V
1.2A to 2.5A
GND
D1: DIODES INC B320B
L1, L2: BH ELECTRONICS BH 510-1009
M1: SILICONIX Si9426
R
C
14.7k
C
C1
4.7nF
C
IN
47μF
X5R
1
2
3
4
5
6
7
8
10
9
C
DC
22μF
X5R
•
R
FB1
2.49k
1%
R
FB2
13.7k
1%
3704 F24
INPUT VOLTAGE (V)
5.0
3704 F25
3.5
4.0
4.5
3.0
I
O(MAX)
(A)
2
3
1
0
OUTPUT CURRENT (A)
0.001
EFFICIENCY (%)
0.1
10
100
95
90
85
80
75
70
65
60
55
50
3704 F26
0.01 1
V
IN
= 5V
V
IN
= 3V
Figure 24. 3V to 5V Input, –8V at 1.2A Output Converter
Figure 26. Output Efficiency at 3V and 5V Input
Figure 25. Maximum Output Current vs Input Voltage
Figure 28.Load Step Response at 5V InputFigure 27. Load Step Response at 3V Input
V
IN
= 3V
V
OUT
(AC)
100mV/DIV
I
OUT
(DC)
0.5A/DIV
250μs/DIV
3704 F27
1.2A
0.6A
V
IN
= 3V
V
OUT
(AC)
100mV/DIV
I
OUT
(DC)
0.5A/DIV
250μs/DIV
3704 F27
1.2A
0.6A