Datasheet

LTC1871-1
32
18711fb
TYPICAL APPLICATIONS
18V to 27V Input, 28V Output, 400W 2-Phase, Low Ripple, Synchronized RF Base Station Power Supply (Boost)
5V to 12V Input, ±12V/0.2A Output SEPIC Converter with Undervoltage Lockout
RUN
I
TH
FB
FREQ
MODE/SYNC
SENSE
V
IN
INTV
CC
GATE
GND
1
2
3
4
5
10
9
8
7
6
LTC1871-1
R
T1
150k
5%
R
S1
0.007Ω
1W
EXT CLOCK
INPUT (200kHz)
R2
8.45k
1%
C
VCC1
4.7µF
X5R
C
IN2
2.2µF
35V
X5R
M1
D1
L2
5.6µH
L5*
0.3µH
C
C1
47pF
C
FB1
47pF
V
IN
18V to 27V
GND
V
OUT
28V
14A
18711 TA04
C
OUT1
2.2µF
35V
X5R
×3
C
OUT2
330µF
50V
C
IN1
: SANYO 50MV330AX
C
IN2, 3
: TAIYO YUDEN GMK325BJ225MN
C
OUT2, 4, 5
: SANYO 50MV330AX
C
OUT1, 3, 6
: TAIYO YUDEN GMK325BJ225MN
C
VCC1, 2
: TAIYO YUDEN LMK316BJ475ML
L1 TO L4: SUMIDA CEP125-5R6MC-HD
L5: SUMIDA CEP125-0R3NC-ND
D1, D2: ON SEMICONDUCTOR MBR2045CT
M1, M2: INTERNATIONAL RECTIFIER IRLZ44NS
R1
93.1k
1%
L1
5.6µH
*L5, C
OUT5
AND
C
OUT6
ARE AN
OPTIONAL SECONDARY
FILTER TO REDUCE
OUTPUT RIPPLE FROM
<500mV
P-P
TO <100mV
P-P
+
C
OUT5
*
330µF
50V
×4
C
OUT6
*
2.2µF
35V
X5R
C
IN1
330µF
50V
RUN
I
TH
FB
FREQ
MODE/SYNC
SENSE
V
IN
INTV
CC
GATE
GND
1
2
3
4
5
10
9
8
7
6
LTC1871-1
R
T2
150k
5%
R3
12.1k
1%
R
C
22k
R4
261k
1%
C
VCC2
4.7µF
X5R
C
IN3
2.2µF
35V
X5R
M2
D2
L4
5.6µH
C
C2
47pF
C
C3
6.8nF
C
FB2
47pF
C
OUT3
2.2µF
35V
X5R
×3
C
OUT4
330µF
50V
L3
5.6µH
+
+
R
S2
0.007Ω
1W
+
RUN
I
TH
FB
FREQ
MODE/SYNC
SENSE
V
IN
INTV
CC
GATE
GND
1
2
3
4
5
10
9
8
7
6
LTC1871-1
R
T
60.4k
1%
R
S
0.02Ω
R4
127Ω
1%
R2
54.9k
1%
R3
1.10k
1%
C
VCC
4.7µF
10V
X5R
C
IN1
1µF
16V
X5R
M1
D1
L1*
•
R
C
22k
C
C1
6.8nF
C
C2
100pF
C
DC1
4.7µF
16V
X5R
V
IN
5V to 12V
V
OUT1
12V
0.4A
GND
V
OUT2
–12V
0.4A
18711 TA03
C
OUT1
4.7µF
16V
X5R
×3
C
OUT2
4.7µF
16V
X5R
×3
D1, D2: MBS120T3
L1 TO L3: COILTRONICS VP1-0076 (*COUPLED INDUCTORS)
M1: SILICONIX/VISHAY Si4840
R1
127k
1%
C
IN2
47µF
16V
AVX
C
DC2
4.7µF
16V
X5R
+
L2*
L3*
D2
•
•
NOTE:
1. V
IN
UVLO
+
= 4.47V
V
IN
UVLO
–
= 4.14V