AP63200Q/AP63201Q/AP63203Q/AP63205Q

Document number: DS43698 Rev. 1 - 2

25 of 30

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September 2021

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AP63200Q/AP63201Q/AP63203Q/AP63205Q

Application Information (continued)

10

Setting the Output Voltage (continued)

Table 1 shows a list of recommended component selections for common AP63200Q/AP63201Q output voltages referencing Figure 1.

Table 1. Recommended Component Selections for AP63200Q/AP63201Q

AP63200Q/AP63201Q

Output Voltage

(V)

R1

(k

Ω)

R2

(k

Ω)

L

(µH)

C1

(µF)

C2

(µF)

C3

(nF)

C4

(pF)

1.2

15.0

30.1

3.3

10

3 x 22

100

100

1.5

26.1

30.1

4.7

10

3 x 22

100

100

1.8

37.4

30.1

4.7

10

2 x 22

100

100

2.5

63.4

30.1

6.8

10

2 x 22

100

100

3.3

93.1

30.1

6.8

10

2 x 22

100

100

5.0

158.0

30.1

10.0

10

2 x 22

100

100

12.0

422.0

30.1

15.0

10

2 x 22

100

56

The AP63203Q/AP63205Q has a fixed output voltage. Table 2 and Table 3 show the recommended component selections for AP63203Q and

AP63205Q referencing Figure 4.

Table 2. Recommended Component Selections for AP63203Q

AP63203Q

Output Voltage

(V)

L

(µH)

C1

(µF)

C2

(µF)

C3

(nF)

3.3

3.3

10

2 x 22

100

Table 3. Recommended Component Selections for AP63205Q

AP63203Q

Output Voltage

(V)

L

(µH)

C1

(µF)

C2

(µF)

C3

(nF)

5.0

4.7

10

2 x 22

100

11

Inductor

Calculating the inductor value is a critical factor in designing a buck converter. For most designs, the following equation can be used to calculate

the inductor value:

������ =

������������������������ ∙ (������������������ − ������������������������)

������������������ ∙ ∆������������ ∙ ������������������

Eq. 7

Where:



∆IL is the inductor current ripple



fSW is the buck converter switching frequency

For the AP63200Q/AP63201Q/AP63203Q/AP63205Q

, choose ∆IL to be 30% to 40% of the maximum load current of 2A.

The inductor peak current is calculated by:

������������

������������������������ = ������������������������������ +

∆������������

������

Eq. 8

Peak current determines the required saturation current rating, which influences the size of the inductor. Saturating the inductor decreases the

converter efficiency while increasing the temperatures of the inductor and the internal power MOSFETs. Therefore, choosing an inductor with the

appropriate saturation current rating is important. For most applications, it is recommended to select an inductor of approximately 3.3µH to 15µH

with a DC current rating of at least 35% higher than the maximum load current. For highest

efficiency, the inductor’s DC resistance should be less

than 3

0mΩ. Use a larger inductance for improved efficiency under light load conditions.