Datasheet

LTC3775
30
3775fa
TYPICAL APPLICATIONS
24V Input, 12V/5A Output at 500kHz
C
B
0.1μF
L1
4.7μH
C
OUT
68μF
16V
s2
C
IN1
330μF
35V
V
IN
24V
V
OUT
12V
5A
3775 TA04
C
VCC
4.7μF
C2
330pF
C1
3.3nF
R
ILIMB
56.2k
R
SET
39.2k
R2
7.68k
R
B
10k
C
OUT
: SANYO 16TQC68M
D
B
: CMDSH4E
L1: IHLP-4040DZ-ER-4R7-M11
Q
B
, Q
T
: RJK0305DPB-00-JO
R
A
191k
R3
2.05k
C3
330pF
R
ILIMT
1.24k
R4
69.8k
R5
10k
D
B
C
SS
0.01μF
TG Q
T
Q
B
V
IN
LTC3775
SGND
SENSE
I
LIMT
I
LIMB
INTV
CC
SS
BG
PGND
MODE/SYNC
COMP
BOOST
SW
FREQ
RUN/SHDN
FB
+
+
Load Step
Effi ciency and Power Loss
vs Load Current
Start-Up
LOAD CURRENT (A)
30
EFFICIENCY (%)
POWER LOSS (W)
90
100
20
10
80
50
70
60
40
0.01 1 10
3775 TA04b
0
1.0
2.5
0.5
2.0
1.5
0
0.1
EFFICIENCY
POWER LOSS
V
IN
= 24V
V
OUT
= 12V
CONTINUOUS MODE
SW FREQ = 500kHz
I
L
5A/DIV
V
OUT(AC)
200mV/DIV
50μs/DIV
3775 TA04c
V
IN
= 24V
V
OUT
= 12V
LOAD = 0A TO 5A TO 0A
MODE = 0V
SW FREQ = 500kHz
I
L
5A/DIV
V
OUT
5V/DIV
V
SS
1V/DIV
2ms/DIV
3775 TA04d
V
IN
= 24V
V
OUT
= 12V
CSS = 0.01μF
MODE = 0V
SW FREQ = 500kHz
SWITCHOVER
FROM PULSE-
SKIPPING TO
CONTINUOUS
MODE