6/9

Axelite Confidential Materials, do not copy or distribute without written consent.

Rev.1.4 Nov.06, 2019

AX5203

Input Capacitor Selection

The input capacitor reduces the surge current drawn from the input and switching

noise from the device. The input capacitor impedance at the switching frequency shall be

less than input source impedance to prevent high frequency switching current passing to

the input. A low ESR input capacitor sized for maximum RMS current must be used.

The capacitor voltage rating should be at least 1.5 times greater than the input

voltage, and often much higher voltage ratings are needed to satisfy.

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. A low ESR capacitor sized for maximum RMS current must be used. The low

ESR requirements needed for low output ripple voltage.

The capacitor voltage rating should be at least 1.5 times greater than the input

voltage, and often much higher voltage ratings are needed to satisfy.

Output Voltage Ripple

Application circuit item shows the basic application circuit with AX5203. The output

voltage ripple (VRIPPLE) very lager at high switch current(ISW=3A, VRIPPLE≒0.7V), external

π

filters can reduce output voltage ripple.

π

filters

VOUT=12V

VCC=5V

C5

4.7uF

L1

22uH

D1 B340A

C8

0.82uF

C10

0.1uF

C4

470uF

R4

11K

C7

0.1uF

R1

100K

C9

330uF

R3

1K

C3

Option

L2

2.2uH

C1

470uF

U1

AX5203

EN

VCC

FB

SS

SW

SW

PGND

SGND