Datasheet

10
LT1931/LT1931A
1931fa
TYPICAL APPLICATIO S
U
V
IN
V
IN
5V
V
OUT
–5V
200mA
1931 TA06a
SW
L1
3.3µH
L2
3.3µH
D1
GND
LT1931A
C1: TAIYO YUDEN X5R JMK212BJ225MG
C2: TAIYO YUDEN X5R LMK212BJ105MG
C3: TAIYO YUDEN X5R JMK212BJ475MG
D1: ON SEMICONDUCTOR MBR0520
L1, L2: PANASONIC ELJPC3R3MF
C1
2.2µF
C3
4.7µF
C2
1µF
R2
10k
R1
28.7k
C4
68pF
NFB
SHDN
LOAD CURRENT (mA)
0
50
EFFICIENCY (%)
55
60
65
70
75
80
50 100 150 200
1931 TA06b
250
2.2MHz, 5V to –5V Converter Uses Tiny Chip Inductors Efficiency
V
IN
V
IN
12V
V
SS
SW
L1
22µH
GND
R2
1k
LT1931
NFB
SHDN
R
SS
15k
R3
25.5k
R1
1Ω
R4
2.7k
C6
1000pF
C
SS
68nF
C1
4.7µF
16V
C3
1µF
35V
*TOTAL OUTPUT POWER NOT TO EXCEED 3.3W
C1 TO C5: X5R OR X7R
D1, D2: BAV99 OR EQUIVALENT
L1: SUMIDA CR43-220
C5
4.7µF
35V
32
D2
1
1931 TA08
C4
4.7µF
35V
V
OUT1
–33V
100mA*
COM
V
OUT2
–66V
48mA*
C2
1µF
35V
32
D1
1
SLIC Power Supply with –33V and – 68V Outputs, Uses Soft-Start