Datasheet

LT3507
26
3507fa
TYPICAL APPLICATIONS
15V, 1.8V and 1.2V 2-Stage Step Down
V
IN1
BOOST1 UVLO
OVLO
PGOOD2
PGOOD3
BOOST 2
SW2
FB2
V
C2
BOOST3
SW3
FB3
TRK/SS2
TRK/SS3
PGOOD1
SW1
FB1
V
C1
TRK/SS1
BIAS
0.1μF
22μF
D1
68.1k
31.6k
220pF
0.01μF
187k
L1 10μH
V
OUT1
15V
0.4A
V
BST
3V
V
IN
21V TO 36V
L2 3.3μH
V
IN2
V
IN3
V
INSW
49.9k 3.4k
UVLO = 19V
11.5k
10.5k
10μF
DRIVE
FB4
TRK/SS4
R
T
/SYNC
V
C3
GND
LT3507
RUN1
RUN2
RUN3
0.1μF
33μF
PGOOD
V
BST
D2
13.3k
SHDN
1000pF
D1: DIODES, INC. B140A
D2, D3: DIODES, INC. B240A
L1: TDK LTF5022T-100M1R4
L2: TDK VLCF5020T-3R3N2R0-1
L3: TDK VLCF5020T-2R2N1R7
Q1: DIODES INC. BC817-16
18.2k
100k
3507 TA04
54.9k
f
SW
= 800kHz
V
OUT2
1.8V
1.5A
22.6k
V
OUT2
L3 2.2μH
0.1μF
47μF
V
BST
D3
12.7k
1000pF
30.1k
270pF
2.2μF
Q1
V
OUT3
1.2V
1.5A
15.0k