TPA3111D1: Series Inductor Selection

Akash Patel

Expert 6245 points

Part Number: TPA3111D1

Hi team,

We are looking to use the TPA3111D1 in our design but are wondering what inductance to use on the output pins.

Looking at page 17 of the TPA3111D1 datasheet, we are seeing 33uH inductors for an 8ohm speaker and 15uH inductors for a 4ohm speaker
Looking at page 3 of the TPA3111D1EVM user's guide, we are seeing 68uH inductors for an 8ohm speaker and 33uH inductors for a 4ohm speaker
Looking at page 5 and 7 of the TPA3111D1EVM user's guide on the Schematic and BoM, we are seeing 22uH inductors

What are the actual recommended inductor values for a 4ohm and 8ohm application?

Regards,

Akash Patel

over 8 years ago

0 Shawn Zheng over 8 years ago

TI__Mastermind 24835 points

Hi Akash,

The the second one, "Looking at page 3 of the TPA3111D1EVM user's guide, we are seeing 68uH inductors for an 8ohm speaker and 33uH inductors for a 4ohm speaker", 68uH is to simulate the inductor in speaker, not about the LC filter.

For the first one and the third one, you can use 22uH+0.68uF or 33uH+1uF for the LC filter. They have the different BW and Q value. The LC design depends on your real application.

Please find the application note about LC filter design http://www.ti.com/lit/an/slaa701a/slaa701a.pdf?keyMatch=slaa701a&tisearch=Search-EN-Everything

and the LC design tool http://www.ti.com/general/docs/lit/getliterature.tsp?baseLiteratureNumber=slac729&fileType=zip

Best regards,

Shawn Zheng

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TPA3111D1: Series Inductor Selection