MAX8643 Maxim Integrated Products, MAX8643 Datasheet - Page 14

• Manufacturer Part Number: MAX8643
• Description: 2MHz Step-Down Regulator
• Manufacturer: Maxim Integrated Products

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3A, 2MHz Step-Down Regulator
with Integrated Switches
Careful PCB layout is critical to achieve clean and stable
operation. It is highly recommended to duplicate the
MAX8643 EV kit layout for optimum performance. If devia-
tion is necessary, follow these guidelines for good PCB
layout:
1) Connect input and output capacitors to the power
2) Place capacitors on V
3) Keep the high-current paths as short and wide as
4) Connect IN, LX, and PGND separately to a large
5) Ensure all feedback connections are short and
6) Route high-speed switching nodes, such as LX,
14
ground plane; connect all other capacitors to the sig-
nal ground plane.
possible to the IC and its corresponding pin using
direct traces. Keep power ground plane (connected
to PGND) and signal ground plane (connected to
GND) separate.
possible. Keep the path of switching current short
and minimize the loop area formed by LX, the out-
put capacitors, and the input capacitors.
copper area to help cool the IC to further improve
efficiency and long-term reliability.
direct. Place the feedback resistors and compensa-
tion components as close to the IC as possible.
away from sensitive analog areas (FB, COMP).
______________________________________________________________________________________
PCB Layout Considerations and
DD
Thermal Performance
, V
IN
, and SS as close as
PROCESS: BiCMOS
TOP VIEW
PGND
PGND
EN
IN
IN
IN
19
20
21
22
23
24
+
18
1
17
2
THIN QFN
MAX8643
16
3
Pin Configuration
Chip Information
15
4
14
5
13
6
12
11
10
9
8
7
PWRGD
FREQ
OUT
FB
COMP
GND