TPA3122D2: Recommended SMT Components for Amp Board

Emmett Palaima78

Part Number: TPA3122D2

Hi, I am looking to make a PCB for 5 TPA3122D2 amplifier chips to drive a total of 10 small speakers. In order to save space I would ideally like to use SMT components for the circuitry surrounding the amplifier.

I would like to know which components are recommend for this, specifically for the output capacitors and inductors. I have tried building this circuit on a breadboard and had it not work because the components did not meet the requirements for a class D amplifier output, which unfortunately are not clearly specified in the datasheet. Furthermore a lot of the components used in the EVM seem to be out of production without datasheets available, so I cannot check the components there.

Can anyone recommend which components I should use, or what the requirements are for output caps and inductors for this amplifier chip?

over 5 years ago

0 Xiaolin Qin over 5 years ago

TI__Expert 6295 points

what is output power range, Load and PVDD? based on those info, our team can propose BOM selection for you.

0 Emmett Palaima78 over 5 years ago in reply to Xiaolin Qin

Prodigy 90 points

I would like to design this board to be fairly versatile.

I would for the board to be able to operate under the following conditions:

Load: 4 Ohm or 8 Ohm Speaker

PVDD: 12V or 24V

Output Power: I am unsure how to properly calculate this, since these are meant to amplify whatever audio content I give them as an input. I guess assume clipping white noise with a 4 Ohm load with a 24V supply for absolute maximum stress conditions. And no input for minimum stress condition. Does this give you the information you need to work with? If not can you provide guidelines for how to calculate this?

In terms of BOM selection, I need the parts to be readily available from either Mouser or DigiKey. Small footprint SMT is preferable, though small footprint through hole could be considered.

Thank you for your quick reply!

0 Emmett Palaima78 over 5 years ago in reply to Emmett Palaima78

Prodigy 90 points

Also, if I am able to use something like this ferrite bead in place of the large inductor that would be highly preferable: www.mouser.com/.../MPZ2012S221A

I have seen this work in other class D amplifier designs and the low cost and small footprint are both very helpful.

0 Emmett Palaima78 over 5 years ago in reply to Xiaolin Qin

Prodigy 90 points

Any word on whether your team can help with component selection?

0 Xiaolin Qin over 5 years ago in reply to Emmett Palaima78

TI__Expert 6295 points

hello,

for you listed condition, are you ok to follow up EVM BOM to do component reference?www.ti.com/.../slou214a.pdf

for any specific component you prefer to change or not easy to buy, you can give what you to us, we can help to double confirm.

regards
Linda

0 Emmett Palaima78 over 5 years ago in reply to Xiaolin Qin

Prodigy 90 points

Hi, the components I would like to find replacements for are L1-L2 (A7503AY-220M 22uH Inductor) and C9, C16 (B32529C684J Metal Poly 0.68uf cap).

I would like to find small surface mount components to replace both (footprint < 1 cm^2 if possible), as inexpensive as possible and available + regularly stocking on mouser or Digikey. What do you recommend?

Thanks for your reply.

0 Xiaolin Qin over 5 years ago in reply to Emmett Palaima78

TI__Expert 6295 points

hello,

for inductor selection, if you dont need higher power and you can select lower Isat inductor, it could be smaller. also 2:1 inductor could be also option.
for C9, C16, 0.68uF inductor, if you want to select smaller one. keep it 1.5x PVDD voltage Max voltage could be ok.

Regards
Linda

0 Emmett Palaima78 over 5 years ago in reply to Xiaolin Qin

Prodigy 90 points

Could you include a link to an inductor and a capacitor you recommend based on my specifications?

0 Xiaolin Qin over 5 years ago in reply to Emmett Palaima78

TI__Expert 6295 points

hello,
you can contact with coilmaster people to get 2:1 inductors which may help you.

markyang@coilmaster.com

inductor value you can keep 22uH.

regards
Linda

0 Emmett Palaima78 over 5 years ago in reply to Xiaolin Qin

Prodigy 90 points

What is the SRF requirement of the inductor for this chip?

Also is component choice for the capacitor trivial?

0 Dylan Yao over 5 years ago in reply to Emmett Palaima78

TI__Genius 9230 points

Emmett,

There is not special requirement about SRF, as it is more for EMI consideration, usually we think it is higher than 10MHz would be good.

capacitor is important for audio performance THD, usually film capacitor has the best performance.

Dylan

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TPA3122D2: Recommended SMT Components for Amp Board