Rainbow Electronics MAX15041 User Manual
Page 15
MAX15041
Low-Cost, 3A, 4.5V to 28V Input, 350kHz, PWM
Step-Down DC-DC Regulator with Internal Switches
______________________________________________________________________________________
15
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).
MAX15041
IN
EN
L
4.7
µH
D
R
BST
47
Ω
INPUT
4.5V TO 28V
BST
OUTPUT = 3.3V
LX
PGND
FB
COMP
R
PU
10k
Ω
C
VDD
1
µF
C
BST
C
OUT
22
µF
R
1
45.3k
Ω
1%
R
1
10.0k
Ω
1%
R
C
1.8k
Ω
C
C
12nF
C
CC
100pF
C
IN
47
µF
C
SS
0.01
µF
V
DD
PGOOD
PGOOD
SS
I.C.
SGND
V
OUT
(V)
L (µH)
C
C
(nF)
R
C
(k
Ω)
R
1
and R
2
5.0
4.7
8
2.70
3.3
4.7
12
1.80
2.5
3.3
22
1.50
1.8
2.2
33
1.00
1.2
2.2
47
0.68
Select R
2
so that:
5k
Ω ≤ R
2
≤ 50kΩ
Calculate R
1
using the equation in the
Setting the Output Voltage section.
Figure 3. Typical Operating Circuit 1 (4.5V to 28V Input Buck Converter)
Table 1. Typical Component Values for Common Output-Voltage Settings