TUSS4470: Empedans Matching and Cabling

Metin Enes Yildirim

Part Number: TUSS4470

Tool/software:

Hello,

I am planning to use TUSS4470 with CUSP-TR12-010-1150 transducer for anemometric. Am I need to make empedans matching between TUSS4470 and CUSP-TR12-010-1150. Is it more convenient to use coaxial cable and SMA connector to maintain impedance matching?

4 months ago

+1 Eddie LaCost 4 months ago

TI__Mastermind 43850 points

Hello Metin,

Yes, there should be impedance matching between the TUSS4470 and transducer. R13 is used for impedance matching in the EVM. Coax or twisted pair can be used for the cabling.

...

0 Metin Enes Yildirim 4 months ago in reply to Eddie LaCost

Prodigy 125 points

Hello Eddie,

Thanks for your reply. I think your refering to BOOSTXL-TUSS4470 as EVM. I want to use it as a reference design but I could not find its design files. Can you help me out?

0 Eddie LaCost 4 months ago in reply to Metin Enes Yildirim

TI__Mastermind 43850 points

Metin,

Please see the smaller reference design below which can be used.

https://www.ti.com/lit/zip/sldc022

If you also require the BOOSTXL-TUSS4470, please send me a friend request and I can send them.

0 Metin Enes Yildirim 4 months ago in reply to Eddie LaCost

Prodigy 125 points

Hello again Eddie,

There is one point I don't understand while reviewing the BOOSTXL-TUSS4470 and TUSS4470PSM design files. I plan to drive my tranducer with direct drive. In the BOOSTXL-TUSS4470 design files, C10 and R13 elements seem to be given for impedance matching. Do these elements need to be used in circuits to be made with transformers or should I use them in direct drive? In the TUSS4470PSM design schematic, R5 resistor is used in the same connection as R13 in the BOOSTXL-TUSS4470 schematic. Should this resistor be used in direct drive? If I need to use it, what exactly is its purpose and how should I determine the resistance value?

BOOSTXL-TUSS4470 schematic:

TUSS4470PSM schematic:

0 Eddie LaCost 4 months ago in reply to Metin Enes Yildirim

TI__Mastermind 43850 points

Yes, you should still use C10 and R13 for transducer drive applications. The transducer drive configuration is still using the nets X+ and X-, which are connected to C10 and R13.

0 Metin Enes Yildirim 4 months ago in reply to Eddie LaCost

Prodigy 125 points

I saw X+ and X- connection to C10 and R13 but in the design file and default PCB board for direct drive these components not fitted. What are these resistor and capasitor purpose? How should I determine the values?

Thanks for the answers.

Best Regards.

+1 Eddie LaCost 4 months ago in reply to Metin Enes Yildirim

TI__Mastermind 43850 points

Metin,

Ah, I see. Yes, these components could be used for direct drive, but not typically required. For transformer driver, see section 4.4.2 and 4.4.3 of the app note below. These components are used for dampening to reduce the decay time and matching to the transformer.

https://www.ti.com/lit/an/slaa732a/slaa732a.pdf

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TUSS4470: Empedans Matching and Cabling