Datasheet

LTC1871
31
1871fe
APPLICATIONS INFORMATION
Figure 19. LTC1871 SEPIC Converter Load Step Response
V
OUT
(AC)
200mV/DIV
I
OUT
0.5A/DIV
50µs/DIV
1871 F19
V
IN
= 15V
V
OUT
= 12V
V
OUT
(AC)
200mV/DIV
I
OUT
0.5A/DIV
50µs/DIV
V
IN
= 4.5V
V
OUT
= 12V
TYPICAL APPLICATIONS
2.5V to 3.3V Input, 5V/2A Output Boost Converter
Output Effi ciency at 2.5V and 3.3V Input
RUN
I
TH
FB
FREQ
MODE/SYNC
SENSE
V
IN
INTV
CC
GATE
GND
1
2
3
4
5
10
9
8
7
6
LTC1871
R
T
80.6k
1%
R1
12.1k
1%
R2
37.4k
1%
C
VCC
4.7µF
X5R
C
IN
47µF
6.3V
M1
C
IN
: SANYO POSCAP 6TPA47M
C
OUT1
: SANYO POSCAP 6TPB150M
C
OUT2
: TAIYO YUDEN JMK316BJ106ML
C
VCC
: TAIYO YUDEN LMK316BJ475ML
D1
L1
1.8µH
R
C
22k
C
C1
6.8nF
C
C2
47pF
C
OUT1
150µF
6.3V
×2
V
IN
2.5V to 3.3V
V
OUT
5V
2A
GND
1871 TA01a
+
C
OUT2
10µF
6.3V
X5R
×2
D1: INTERNATIONAL RECTIFIER 30BQ015
L1: TOKO DS104C2 B952AS-1R8N
M1: SILICONIX/VISHAY Si9426
+
OUTPUT CURRENT (A)
65
EFFICIENCY (%)
95
100
60
55
90
75
85
80
70
0.001 0.1 1 10
1871 TA01b
50
0.01