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

Rev.1.4 Oct.16, 2019

AX3304/A

Inductor Selection

For most designs, the different frequency can be reducing the inductor value; The

AX3304/A is suggested 22µH to 100µH for 100K to 300KHz frequencies. Please refer the

below table to design.

L1 recommend value (VIN=10~30V ,VOUT=5V, IOUT=2A)

Version

AX3304

AX3304A

L1 Value (H)

68~100u

22~47u

Where is inductor Ripple Current. Large value inductors lower ripple current and small

value inductors result in high ripple currents. Choose inductor ripple current approximately

20% of the maximum load current 3A, ΔIL=0.6A. The DC current rating of the inductor

should be at least equal to the maximum load current plus half the ripple current to prevent

core saturation (3A+0.3A).

Input Capacitor Selection

This capacitor should be located close to the IC using short leads and the voltage

rating should be approximately 1.5 times the maximum input voltage. The RMS current

rating requirement for the input capacitor of a buck regulator is approximately 1⁄2 the DC

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

220~470µF low ESR capacitor for most applications is sufficient.

Output Capacitor Selection

The output capacitor is required to filter the output and provide regulator loop stability.

The important capacitor parameters are; the 100 KHz Equivalent Series Resistance (ESR),

the RMS ripples current rating, voltage rating, and capacitance value. For the output

capacitor, the ESR value is the most important parameter. The ESR can be calculated

from the following formula.

ESR

I

V

L

RIPPLE







= 0.6A x 80mΩ= 48mV