Datasheet

LT3990/LT3990-3.3/LT3990-5
18
3990fa
TYPICAL APPLICATIONS
12V Step-Down Converter
5V, 2MHz Step-Down Converter
V
IN
BOOST
LT3990
SWEN/ULVO
PG
RT
C3
0.1µF
22pF
127k
f = 1MHz
C2
22µF
C1
2.2µF
V
IN
15V TO 62V
V
OUT
12V
350mA
R1
1M
R2
113k
L1
33µH
BD
FB
GND
OFF ON
3990 TA06
V
IN
BOOST
LT3990
SWEN/UVLO
PG
RT
51.1k
f = 2MHz
C3
0.1µF
22pF
C2
10µF
C1
1µF
V
IN
8.5V TO 16V
TRANSIENTS
TO 62V
V
OUT
5V
350mA
R1
1M
R2
316k
L1
10µH
BD
FB
GND
OFF ON
3990 TA07
5V Step-Down Converter with Undervoltage Lockout
V
IN
BOOST
LT3990
SWEN/UVLO
PG
RT
0.22µF
22pF
22µF
2.2µF
V
IN
6.5V TO 62V
V
OUT
5V
350mA
1M
316k
374k
5.6M
kΩ
f = 400kHz
33µH
BD
FB
GND
3990 TA08a
1.3M
+
–
Input Current During Start-Up
INPUT VOLTAGE (V)
0
–0.5
INPUT CURRENT (mA)
0.5
1.5
2.5
2
4
6 8
3990 TA08b
10
3.5
4.5
0
1.0
2.0
3.0
4.0
12
INPUT CURRENT
DROPOUT
CONDITIONS
FRONT PAGE
APPLICATION
FRONT PAGE
APPLICATION
WITH UVLO
PROGRAMMED
TO 6.5V
Start-Up from High Impedance Input Source
V
OUT
2V/DIV
V
IN
5V/DIV
5ms/DIV
FRONT PAGE APPLICATION
V
IN
= 12V
V
OUT
= 5V
1k INPUT SOURCE RESISTANCE
2.5mA LOAD
3990 TA08c
UVLO PROGRAMMED TO 6.5V