TPA3220: Using the internal 5V0 LDO

Nick Fletcher

Prodigy 90 points

Part Number: TPA3220

I'm trying to use the internal LDO in the TPA3220 and I must be doing something really silly as I can't get it to work

I am feeding the same voltage to the VDD (pin1) as I am into the PVDD pins - 30V

I have disconnected AVDD and GVDD from the VDD pin

When I power up I m expecting to see 5V0 on the AVDD (pin 21) but I only get 0V

Is there something else that needs to be done to activate the internal LDO regulator?

Just for the record I also have the recommended filter on GVDD and decoupling capacitors. The chip works fine with an external 5V0 regulator but I was trying to reduce the component count

Thanks in advance

over 5 years ago

0 Luis Fernandes de Pina over 5 years ago

TI__Genius 14640 points

Hello Nick,

Can I see your schematic.

Best Regards,

Luis

0 Nick Fletcher over 5 years ago in reply to Luis Fernandes de Pina

Prodigy 90 points

HI Luis,

yes of courseLA-PA2-50W-02.pdf

0 Nick Fletcher over 5 years ago in reply to Luis Fernandes de Pina

Prodigy 90 points

Forgot to say, I have the same issue with the micro dev board too even after I have configured it as per the manual

0 Luis Fernandes de Pina over 5 years ago in reply to Nick Fletcher

TI__Genius 14640 points

Hello Nick,

For the issue with the TPA3220EVM-Micro, there is a mistake in the Table 8 for the LDO Mode configuration, R14(the 5V to GVDD connector) says it should be populated. This is incorrect R14 should be removed and you will get the correct voltage at AVDD and GVDD. We will try to correct this problem with the user's guide as soon as possible. If you make this correction in your connections on your design it should work.

Best Regards,

Luis

0 Nick Fletcher over 5 years ago in reply to Luis Fernandes de Pina

Prodigy 90 points

Hi Luis,

Thanks for the reply

I have removed R14 on the micro board and I still don't appear to have 5V on AVDD?

Kind regards

Nick

0 Nick Fletcher over 5 years ago in reply to Luis Fernandes de Pina

Prodigy 90 points

HI Luis,

Also looking to the schematics of the TPA3220-EVM-Micro wouldn't removing R14 just disable the 5V to the status LEDs and the Reset circuits? As Table 18 has instructions to remove the on board 5V regulator components so this shouldn't be an issue

Kind regards

Nick

0 Luis Fernandes de Pina over 5 years ago in reply to Nick Fletcher

TI__Genius 14640 points

Hey Nick,

Can you send me the picture of your Micro EVM with the board modifications you have done.

Best Regards,

Luis

0 Nick Fletcher over 5 years ago in reply to Luis Fernandes de Pina

Prodigy 90 points

Hi Luis,

I've uploaded a picture where you can see the mods

I just created a solder link on R16 but I get the correct voltage on pin 1 VDD but nothing on pin 21

Kind regards

Nick

0 Luis Fernandes de Pina over 5 years ago in reply to Nick Fletcher

TI__Genius 14640 points

I was unable to replicate the behavior you were observing, can you confirm that the device is still operating with the external 5V configuration.

Best Regards,

Luis

0 Nick Fletcher over 5 years ago in reply to Luis Fernandes de Pina

Prodigy 90 points

Hi Luis,

Are you saying you want me to modify the board back to how it was?

I have the same issue on three different boards all different layouts, on the TI dev board and two different PCB layouts that I have made for customers

All three boards worked fine in their original implementation using a separate regulator on the PCB (TI dev board and my two layouts) just when modified as per the data sheet I do not get 5V at the AVDD pin

Are you also saying that the internal 5V0 LDO works on your copy?

Kind regards

Nick

0 Luis Fernandes de Pina over 5 years ago in reply to Nick Fletcher

TI__Genius 14640 points

Hello Nick,

I found the fix to your problem. When you disconnect the components from the external 5V for the internal LDO configuration you cannot power the reset pin so the device off because reset is held low.

Given R14 is connected, If you connect R32 to 5V(I did so with an external power supply) as shown in the image below, Reset goes high which turns Reset off and the device turns on. At this point the internal LDO is working at you get the correct voltages on GVDD and AVDD. The device stays on if R14 is connected because pull up resistor on reset is getting 5V from GVDD so Reset is held high.

So for the TPA3220EVM-Micro to use the internal LDO and following the modifications in the user's guide, you need to externally clear reset. This can be done from either shorting/connecting R32 to 5V or using Audio Interface Board reset pin(Pin 10 on J3).

0 Nick Fletcher over 5 years ago in reply to Luis Fernandes de Pina

Prodigy 90 points

Hi Luis,

Thank you

That works perfectly on all the boards

I'm guessing a few extra lines will get added to the data sheet!

Thanks again

Kind regards

Nick

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TPA3220: Using the internal 5V0 LDO