Datasheet

LT3757/LT3757A
31
3757afe
For more information www.linear.com/LT3757
Typical applicaTions
5.5V to 36V Input, 12V/2A Output SEPIC Converter
Efficiency vs Output Current Load Step Waveforms
Start-Up Waveforms Frequency Foldback Waveforms When Output Short-Circuits
SENSE
LT3757A
V
IN
V
IN
5.5V TO 36V
C
IN1
4.7µF
50V
×2
C
DC
4.7µF
50V, X5R, ×2
4.7µF
10V
X5R
V
OUT
12V
2A
0.01Ω
1W
M1
41.2k
300kHz
GATE
FBX
GND
INTV
CC
SHDN/UVLO
SYNC
RT
SS
C
IN2
4.7µF
50V
×2
•
•
105k
46.4k
0.1µF
6.8nF
10k
L1A
L1B
I
L1B
D1
C
IN1
, C
DC
: TAIYO YUDEN UMK316BJ475KL
C
IN2
: KEMET T495X475K050AS
C
OUT1
: KEMET T495X476K020AS
C
OUT2
: TAIYO YUDEN TMK432BJ106MM
D1: ON SEMI MBRS360T3G
L1A, L1B: COILTRONICS DRQ127-4R7 (*COUPLED INDUCTORS)
M1: VISHAY SILICONIX Si7460DP
3757 TA06a
105k
1%
15.8k
1%
C
OUT1
47µF
20V
×4
C
OUT2
10µF
25V
X5R
+
V
SW
I
L1A
V
C
+
2ms/DIV
V
OUT
5V/DIV
I
L1A
+ I
L1B
5A/DIV
3757 TA06d
V
IN
= 12V
50µs/DIV
V
OUT
10V/DIV
V
SW
20V/DIV
I
L1A
+ I
L1B
5A/DIV
3757 TA06e
V
IN
= 12V
OUTPUT CURRENT (A)
0.001
20
EFFICIENCY (%)
30
40
50
60
70
80
90
100
0.01
0.1 1
3757 TA06b
10
V
IN
= 16V
V
IN
= 8V
500µs/DIV
V
OUT
2V/DIV
AC-COUPLED
I
OUT
2A/DIV
0A
2A
3757 TA06c
V
IN
= 12V
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