LTC1504A
BLOCK DIAGRAM
SHDN
COMP
12µA
SS
I
MAX
12µA
20.4k
FB
(ADJ ONLY)
SENSE
(–3.3V ONLY)
TEST CIRCUITS
NC
I
MAX
V
CC
SHDN
SW
LTC1504A
GND
SS
FB/SENSE
COMP
L
EXT
47µH
V
OUT
+
V
CC
C
IN
100µF
1µF
C
IN
: AVX TPSE107M016R0125
C
OUT
: SANYO 16CV220GX
L
EXT
: COILCRAFT D03316-473
Figure 1
APPLICATIONS INFORMATION
OVERVIEW
The LTC1504A is a complete synchronous switching
regulator controller (see Block Diagram). It includes two
on-chip 1.3Ω power MOSFETs, eliminating the need for
external power devices and minimizing external parts
count. The internal switches are set up as a synchronous
buck converter with a P-channel device (Q1) from the
input supply to the switching node and an N-channel
device (Q2) as the synchronous rectifier device from the
switching node to ground. An external inductor, input and
U
W
W
TO INTERNAL BLOCKS
V
CC
Q1
SAW
–
PWM
SW
+
Q2
I
LIM
FB
–
+
+
–
+
–
V
REF
1.265V
12.6k
1504A • BD
Figure 3. Block Diagram
LTC1504A
A
B
C
OUT
220µF
FB/SENSE
–
COMP
+
+
V
REF
0.1µF
7.5k
0.01µF
220pF
A: TEST V
OL
, I
OL
B: TEST V
OH
, I
OH
1504A • TC02
1504A • TC01
Figure 2
U
U
5
LINER [ LINEAR TECHNOLOGY ]
