MPQ4458 –INDUSTRIAL GRADE,1A, 4MHz, 36V STEP-DOWN CONVERTER

MPQ4458 Rev. 1.0

www.MonolithicPower.com

15

12/5/2012

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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

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

VIN

EN

FREQ

GND

BST

SW

FB

COMP

MPQ4458

EN

R5

R6

R3

R4

MPQ4458 Typical Application Circuit

Top Layer

Bottom Layer

Figure 4―MPQ4458 Typical Application Circuit and PCB Layout Guide