MPQ4459 – INDUSTRIAL GRADE, 1.5A, 4MHz, 36V STEP-DOWN CONVERTER
MPQ4459 Rev. 1.01 www.MonolithicPower.com 16
1/24/2014 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
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PCB LAYOUT GUIDE
PCB layout is very important to achieve stable
operation. It is highly recommended to duplicate
EVB layout for optimum performance.
If change is necessary, please follow these
guidelines and take Figure 4 for reference.
1) Keep the path of switching current short
and minimize the loop area formed by Input
cap, high-side MOSFET and external
switching diode.
2) Bypass ceramic capacitors are suggested
to be put close to the V
IN
Pin.
3) Ensure all feedback connections are short
and direct. Place the feedback resistors
and compensation components as close to
the chip as possible.
4) Route SW away from sensitive analog
areas such as FB.
5) Connect IN, SW, and especially GND
respectively to a large copper area to cool
the chip to improve thermal performance
and long-term reliability.
C1
C3
R2
R1
L1
C4
C2
D1
V
OUT
V
IN
VIN
EN
FREQ
GND
BST
SW
FB
COMP
MPQ4459
EN
R5
R6
R3
R4
MPQ4459 Typical Application Circuit
TOP Layer Bottom Layer
Figure 4―MPQ4459 Typical Application Circuit and PCB Layout Guide
C4
C1
R1
GNDGND
Vin
Vo
SW
L1
C2
D1
R6
