Datasheet

LT3957A
25
3957afa
TYPICAL APPLICATIONS
5V to 16V Input, –12V Output Inverting Converter
Efficiency vs Output Current
Load Step Waveforms
Start-Up Waveforms
Frequency Foldback Waveforms
When Output Short-Circuit
SENSE2
SENSE1
LT3957A
L1A L1B
V
IN
SW
GND
FBX
RT SS
INTV
CC
EN/UVLO
SYNC
SGND
82.5k
V
C
395A7 TA04a
D1
200k
41.2k
300kHz
C
VCC
4.7µF
10V
X5R
0.47µF
10k
10nF
105k
7.5k
C
DC
4.7µF, 50V
X7R
V
OUT
–12V
1A
V
IN
5V TO 16V
C
IN
4.7µF
25V
X5R
C
OUT
22µF
16V
X5R
w2
t t
C
IN
: MURATA GRM21BR61E475KA12L
C
DC
: TAIYO YUDEN UMK316BJ475KL
C
OUT
: MURATA GRM32ER61C226KE20
D1: VISHAY SILICONIX 30BQ040
L1A, L1B: COILTRONICS DRQ127-100
OUTPUT CURRENT (mA)
0
50
EFFICIENCY (%)
65
60
55
70
75
80
85
90
95
100
200 400 600
800
3957A TA04b
1000
V
IN
= 12V
5ms/DIV
V
OUT
5V/DIV
I
L1A
+ I
L1B
2A/DIV
3957A TA04d
V
IN
= 12V
50µs/DIV
V
OUT
10V/DIV
V
SW
20V/DIV
I
L1A
+ I
L1B
5A/DIV
3957A TA04e
V
IN
= 12V
2ms/DIV
V
OUT
1V/DIV
(AC)
I
OUT
0.2A/DIV
0.6A
0A
3957A TA04c
V
IN
= 12V