LT1940/LT1940L
U
TYPICAL APPLICATIO S
3.3V and 1.8V Outputs with Sequencing
V
IN
4.7V TO 14V
C3
D3
V
D4
IN
4.7µF
OUT2
3.3V
1A
BOOST1 BOOST2
LT1940
Start-Up Waveforms
(1.4A FOR V > 5V)
IN
L1
2.2µH
L2
3.3µH
0.1µF
0.1µF
OUT1
1.8V
1.4A
SW1
SW2
V
IN
2V/DIV
D1
D2
10.0k
16.5k
FB1
FB2
V
OUT1
2V/DIV
V
V
C2
C1
V
OUT2
2V/DIV
C1
22µF
C2
10µF
20k
220pF
15k
330pF
22.6k
RUN/SS1
PG1
PG2
10.0k
100k
POWER GOOD
2V/DIV
RUN/SS2
GND
1nF
1940 TA01b
50µs/DIV
POWER
GOOD
1940 TA01
C1: TAIYO YUDEN JMK316BJ226ML
C2: TAIYO YUDEN JMK316BJ106ML
C3: TAIYO YUDEN EMK316BJ475ML
D1, D2: MICROSEMI UPS120
D3, D4: CENTRAL CMDSH-3
L1: SUMIDA CR43-2R2
L2: SUMIDA CR43-3R3
5V/3.3V with Tantalum Output Capacitors
V
IN
7V TO 25V
C3
4.7µF
D4
V
IN
D3
OUT2
5V
1.2A
BOOST1 BOOST2
LT1940
L1
3.3µH
L2
4.7µH
0.1µF
0.1µF
OUT1
3.3V
1.2A
SW1
SW2
D1
D2
16.5k
10.0k
30.1k
FB1
FB2
V
V
C1
C2
+
C1
C2
+
100µF
10.0k
220pF
20k
100pF
PG1
PG2
10.0k
100k
47µF
6.3V
10V
RUN/SS1 RUN/SS2
GND
100k
1nF
1nF
3V3
GOOD
5 GOOD
1940 TA03
C1: AVX TPSC107M010R0150
C2: AVX TPSC476M010R0350
C3: TAIYO YUDEN TMK325BJ475ML
D1, D2: MICROSEMI UPS140 OR ON SEMI MBRM140
D3, D4: CENTRAL CMDSH-3
L1: SUMIDA CDRH4D28-3R3
L2: SUMIDA CDRH4D28-4R7
1940fa
17
Linear [ Linear ]
