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

Rev.1.4 Oct.04, 2019

AX3015

Line Compensation

The function is designed in order to compensate the output line loss, especially in

heavy load. The AX3015 load regulation is positive; the VOUT voltage can be raised by

output current. For example, VFB=1.08V in IOUT=0A, When IOUT increase to 1A, the VFB can

be rise to about 1.123V.

Inductor Selection

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

AX3015 is suggested 68µH to 120µH for 130KHz frequencies. Please refer the below

table to design.

L1 recommend value (VIN=10~30V ,VOUT=5V, IOUT=1A)

Version

AX3015

L1 Value (H)

68u~100u

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 2A, ΔIL=0.4A. 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 (2A+0.2A).

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

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.