TPA3251: Inconsistency between datasheet and EVM - use of 3.3 ohm resistor

Supira Medical

Part Number: TPA3251

Tool/software:

HI,

In the datasheet application section (Fig. 25). there is a 3.3 ohm resistor in series with the GVdd pin but in the EVM schematics, the resistor is on the Vdd pin instead. Which is correct?

Thanks!

3 months ago

0 Sydney Northcutt 3 months ago

TI__Genius 17960 points

Hello,

Thanks for reaching out.

This resistor is connected between GVDD and VDD in both schematics. One end of the resistor is connected to VDD while the other end is connected to GVDD.

Regards,
Sydney Northcutt

0 Supira Medical 3 months ago in reply to Sydney Northcutt

Intellectual 300 points

Hi Sydney,

Sorry, I wasn't clear in my question. You are correct that the 3.3 ohm resistor is connected between the VDD and GVDD_AB pins. The difference lies in how the resistor is connected to +12volts. In the EVM, the 12 volt feed to the VDD pin goes through the resistor but in the datasheet it's reversed. The first image is the EVM and the second the datasheet:

0 Sydney Northcutt 3 months ago in reply to Supira Medical

TI__Genius 17960 points

Hi,

Ah I see. Thank you for clarifying! This EVM was designed a while ago but I found a previous thread that offers insight on the difference: https://e2e.ti.com/support/audio-group/audio/f/audio-forum/698972/tpa3251-vdd-input?tisearch=e2e-sitesearch&keymatch=tpa3251%25203.3%2520ohm%2520on%2520gvdd#

Overall this was done on the EVM to add versatility so the user can include filtering when necessary so it is recommended to keep the footprints and populate as needed.

Regards,
Sydney Northcutt

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TPA3251: Inconsistency between datasheet and EVM - use of 3.3 ohm resistor