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

Rev.1.5 Oct.15, 2019

AX3116

Table 1 Resistor select for output voltage setting

VOUT

R6

R5

5V

1.3K

6.8K

3.3V

1.5K

4.7K

2.5V

2.2K

4.7K

1.8V

2K

2.5K

1.5V

2.2K

2.0K

1.2V

3K

1.5K

1.0V

3K

0.75K

RDS (ON) Current Limiting

The current limit threshold is setting by the external resistor (R2) connecting from VCC

supply to OCSET pin. The internal 110uA sink current crossing the resistor sets the voltage at

pin of OCSET. When the PWM voltage is less than the voltage at OCSET, an over-current

condition is triggered. Please refer to the formula for setting the current limit value:

R

I

I

DS(ON)

OCSET

SW(MIN)

05

0

R2

.







(Normally, The ISW(MAX) setting more than IOUT 1.0A .)

Example:

ISW = (110u x 2K + 0.05)/ 45m= 6.67A (VIN=12V)

ISW = (110u x 3.75K + 0.05)/ 70m= 6.6A (VIN=5V)

Inductor Selection

For most designs, the operating inductor range is 10µH to 15µH. The inductor value

can be derived from the following equation:





f

I

V

V

V

V

L

OSC

L

IN

OUT

IN

OUT













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

15% of the maximum load current 5A, ΔIL=0.75A. 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 (5A+0.38A)

(TA=25°C)