Datasheet

LT3959
21
3959fa
For more information www.linear.com/LT3959
Typical applicaTions
2.5V to 24V Input, 12V Output SEPIC Converter
DRIVE
LT3959
L1A
L1B
V
IN
V
C
SW
D1
L1A, L1B: COILTRONICS DRQ127-150
D1: VISHAY 6CWQ06FN
GND
FBX
RT
SS
INTV
CC
EN/UVLO
SYNC
TIE TO SGND IF
NOT USED
PGOOD
SGND
3959 TA03
124k
121k150k
7.5k 4.7µF
27.4k
300kHz
22nF0.1µF
105k
15.8k
GNDK
4.7µF
50V
V
OUT
12V
500mA AT V
IN
= 2.5V
1.5A AT V
IN
> 8v
V
IN
2.5V TO 24V
C
IN
22µF
50V
×2
C
OUT1
47µF
16V
X5R
×2
•
•
Efficiency vs Output Current
Load Step Response at V
IN
= 12V
Frequency Foldback Waveforms
When Output Short-Circuits
OUTPUT CURRENT (mA)
0
EFFICIENCY (%)
90
100
800
3759 TA03b
80
400200 600 1000
65
70
75
85
95
60
V
IN
= 12V
500µs/DIV
V
OUT
500mV/DIV
(AC)
I
OUT
500mA/DIV
0.2A
0.8A
3959 TA03c
500µs/DIV
V
OUT
10V/DIV
V
SW
20V/DIV
I
L1A+L1B
2.5A/DIV
3959 TA03d