MAX15041_10 Datasheet, PDF (16/18 Pages) Maxim Integrated Products – Low-Cost, 3A, 4.5V to 28V Input, 350kHz, PWM Step-Down DC-DC Regulator with Internal Switches

Low-Cost, 3A, 4.5V to 28V Input, 350kHz, PWM
Step-Down DC-DC Regulator with Internal Switches
2) Place capacitors on V_DD, IN, and SS as close as
possible to the IC and the corresponding pin using
direct traces. Keep the power ground plane (con-
nected to PGND) and signal ground plane (connect-
ed to SGND) separate. PGND and SGND connect at
only one common point near the input bypass
capacitor return terminal.
3) Keep the high-current paths as short and wide as
possible. Keep the path of switching current short
and minimize the loop area formed by LX, the output
capacitors, and the input capacitors.
4) Connect IN, LX, and PGND separately to a large
copper area to help cool the IC to further improve
efficiency.
5) Ensure all feedback connections are short and
direct. Place the feedback resistors and compensa-
tion components as close as possible to the IC.
6) Route high-speed switching nodes (such as LX and
BST) away from sensitive analog areas (such as FB
and COMP).
INPUT
4.5V TO 28V
C_IN
47µF
R_PU
10kΩ
PGOOD
D
R_BST
47Ω
IN
BST
MAX15041
EN
C_BST
10nF
V_DD
LX
C_VDD
1µF
PGND
PGOOD
SS
I.C.
C_SS
0.01µF
FB
COMP
SGND
C_CC
100pF
L
4.7µH
C_OUT
10nF
R_C
1.8kΩ
C_C
12nF
OUTPUT = 3.3V
R₁
45.3kΩ
1%
R₂
10.0kΩ
1%
Figure 3. Typical Operating Circuit (4.5V to 28V Input Buck Converter)
Table 1. Typical Component Values for Common Output-Voltage Settings
V_OUT (V)
5.0
3.3
2.5
1.8
1.2
L (µH)
4.7
4.7
3.3
2.2
2.2
C_C (nF)
8
12
22
33
47
R_C (kΩ)
2.70
1.80
1.50
1.00
0.68
R₁ and R₂
Select R₂ so that:
5kΩ ≤ R₂ ≤ 50kΩ
Calculate R₁ using the equation in the
Setting the Output Voltage section.
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