MPQ4462DQ-AEC1 inductor and feedback network choice - conflicting recommendations

DC-DC Power Converters
1

The datasheet for this device gives a recommended inductance of 15 - 22µH for a 5V output of this , but when calculated using the formula on page 12 of this datasheet, the value ranges between 1.63 and 3.75 µH, when operated with a power supply voltage of up the 36V.

The simulator (MPSApps3.14) recommends a value of 4.7µH. Why does the datasheet recommend such a large value? (Approximately 3x larger).

Also conflicting are recommendations about the feedback network. All of the examples in the datasheet show R2 at 40.2kΩ. The simulator consistently puts R2 at 3.7kΩ which, although satisfying the datasheet criteria of R2 ≤40kΩ, is again a significant deviation (10x). The datasheet does not explain the impact of changes to the value of R2.

Could you please help me make appropriate selections. Many thanks.

2

Hello phil,

I have seen your response and will get to it as soon as possible. I apologize for the delay, we are currently very limited on bandwidth.

Thank you,
Vinh Tran
Field Applications Engineer

3

Hello phil,

The inductor selection will also depend on the desired output current. Please follow the inductor selection equation.

As for R2, as long as it meets the criteria it should be fine. image

Thank you,
Vinh Tran
Field Application Engineer