Low-Cost, High-Frequency, Current-Mode PWM
Buck Controller
MAX1953/MAX1954/MAX1957
V
IN
3V TO 5.5V
C1
3
✕
22µF
R
C
51.1kΩ
COMP
V
DDQ
R1
2kΩ
C
C
470pF
Cf
68pF
C6
10µF
C7
4.7µF
IN
BST
DH
D1
N1
L1
2.7µH
C14
1500pF R3
10kΩ
C2
0.1µF
V
TT
= 1/2 V
DDQ
C3
270µF
C4
270µF
C5
270µF
MAX1957
REFIN
C8
0.1µF
LX
DL
PGND
R2
2kΩ
GND
FB
Figure 3. Typical Application Circuit for the MAX1957
V
HSD
10.8V TO 13.2V
V
IN
3V TO 5.5V
D1
C1
0.22µF
HSD
IN
BST
DH
N1
C7
0.1µF
N3
N4
R1
10kΩ
C8
270µF
C9
270µF
C10
270µF
C11
270µF
C12
270µF
C13
270µF
N2
L1
0.8µH
V
OUT
1.8V AT 20A
C2
10µF
C3
10µF
C4
10µF
C5
10µF
C6
10µF
R
C
270kΩ
C
C
560pF
C
f
15pF
MAX1954
COMP
LX
DL
PGND
GND
FB
R2
8.06kΩ
Figure 4. 20A Circuit
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