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Rev.1.3 Nov.26, 2019

AX3518

Output Capacitor Selection

The output capacitor is required to keep the output voltage ripple small and to ensure

regulation loop stability. The output capacitor must have low impedance at the switching

frequency. Ceramic capacitors with X5R or X7R dielectrics are recommended due to their

low ESR and high ripple current. A 22µF ceramic capacitor for most applications is sufficient.

Compensation Capacitor Selection

The compensation capacitor (C5) for increasing phase margin provides additional

stability. Refer to Demo Board Schematic, The C5 optimum value is 15pF for all conditions.

Layout Guide

AX3518 TDFN-8L and SOP8-EP are the same layout.

PVIN

FB

SGND

LX

REF

SVIN

PGND

AX3518

Expose

Pad

8

1

2

3

4

5

6

7

EN

C1

C3

VIN

R1

L1

VOUT

C2

R2

R3

C3 and C4 must be placed

between pin and SGND as

closer as possible

SW should be connected to Inductor by

wide and short trace, keep sensitive

components away from this trace

C1 must be placed between PVIN and

PGND as closer as possible, VIN trace

should be wide and short.

VIN

C5

GND

C4