Help with schematic UM10422 evaluation board (TDA5051 based)

[george_govaerts]

Hi All

I am an Engineering student (energy, not electrical) and was looking through the UM10422 evaluation board with the TDA5051 chip from NXP. I have a few question regarding the board schematic in figure 10 pag 11of 15 of the UM10422 file.

Where does the + and GND of a DC source go?

Does the + terminal go to JP2 and the GND to JP1?

There are two filters, the first one, highlighted in green. 

This filter is tuned to the carrier frequency fc, this means it blocks all frequencies, except the carrier frequency?

The second part, highlighted in red, what is the function of this part of the circuit? How are these values calculated? Couldn't find the answer in the application note (AN10903)

how does the decoupling of RX_IN AND TX_OUT actually work? What is the function of the capacitors C3 and C6?

Thanks in advance!

George

[guoweisun]

Hi

Please see comment below:

1:Where does the + and GND of a DC source go?

Does the + terminal go to JP2 and the GND to JP1?

[gw]Yes.

2:There are two filters, the first one, highlighted in green. 

This filter is tuned to the carrier frequency fc, this means it blocks all frequencies, except the carrier frequency?

[gw]No,X capacitor combining with single inductor L as a filter which used in frond AC line to optimize EMC of system.

3:The second part, highlighted in red, what is the function of this part of the circuit? How are these values calculated? Couldn't find the answer in the application note (AN10903)

how does the decoupling of RX_IN AND TX_OUT actually work? What is the function of the capacitors C3 and C6?

[gw]Please read AN10903 Coupling with LC filter page 26-28 for more explain.

[george_govaerts]

Thank you for the response!

Is it also possible to explain how exactly the LC-filter connected to the mains helps with EMC?

With kind regards,

George Govaerts

[guoweisun]

In this chance,I just introduce the primitive principle of X capacitor and L filter, The X capacitor is used in the power filter to filter the power supply and the differential mode interference and the single L has the same function with X capacitor.

In realist application need customer to optimize value of LC during EMC test.