Datasheet

LT1946
9
1946fb
TYPICAL APPLICATIO S
U
Low Profile, Triple Output TFT Supply (10V, –10V, 20V)
V
IN
V
IN
3.3V TO 5V
SW
FB
3
8
7
14
2
65
LT1946
L1
5.4µH
D1
R2
10.5k
R1
75k
R
C
33.3k
1946 TA01
C2
20µF
C5
0.1µF
C3
1µF
C4
2.2µF
C1
4.7µF
C
C
470pF
C
SS
100nF
D4
V
OFF
–10V
10mA
AV
DD
10V
450mA, V
IN
= 5V
275mA, V
IN
= 3.3V
V
ON
20V
5mA
D5
C6
0.1µF
V
C
GND
SHDN
SS
COMP
C1 TO C6: X5R OR X7R
C1: 4.7µF, 6.3V
C2: 2 × 10µF, 10V
C3: 1µF, 25V
C4: 2.2µF, 10V
C5, C6: 0.1µF, 10V
D1: MICROSEMI UPS120 OR EQUIVALENT
D2 TO D5: ZETEX BAT54S OR EQUIVALENT
L1: SUMIDA CDRH5D18-5R4
+
D2 D3
OFF ON
AV
DD
LOAD CURRENT (mA)
0
EFFICIENCY (%)
65
70
75
300
500
1946 TA01a
60
55
50
100 200 400
80
85
90
V
IN
= 5V
V
IN
= 3.3V
V
ON
LOAD = 5mA
V
OFF
LOAD = 10mA
Efficiency
AV
DD
50mV/DIV
AC COUPLED
I
LI
0.5A/DIV
V
IN
= 5V 100µs/DIV 1946 TA01b
Transient Response
150mA
100mA
AV
DD
LOAD