TRF0208-SEP: Matching and filter circuit with ADC12DJ5200-SEP

David Park

Expert 6910 points

Part Number: TRF0208-SEP
Other Parts Discussed in Thread: TRF1208, TRF1208EVM, AFE7950-SP, ADC12DJ5200-SEP,

Tool/software:

Hi,

1. could you let me know why this value is selected for R180/185 and R183/188?

Below is the circuit based on TRF1208 but customer will adopt TRF0208.

2. could you let me know what these compents are for?

C91(DNI), L20(DNI), C92(DNI) and C103(DNI), C83(DNI)

5 months ago

0 Hruday Kumar Mudireddy 5 months ago

TI__Expert 4580 points

Hi David,

Can you elaborate your application? 1st image refers to TRF1208EVM, in second image you have matching components to match impedance of AFE7950-SP.

Regards,

Hruday

0 David Park 5 months ago in reply to Hruday Kumar Mudireddy

TI__Expert 6910 points

Hi Kumar,

As title, customer will useTRF0208-SEP with ADC12DJ5200-SEP.

Because there is no reference circuit, they are referring TRF1208EVM and TRF0208-SEP+AFE7950-SP reference circuit.

Customer's board max frequency is 1.95GHz.

Thanks.

0 Hruday Kumar Mudireddy 5 months ago in reply to David Park

TI__Expert 4580 points

Hi David,

Thanks for clarification. The intent of pads on the output of TRF1208 is to transform the low output impedence of Amps to 100ohm differential. Then series and shunt inductors are available to implement anti aliasing filter + match the ADC. Customer can implement as below: Let me know if any further questions arise.

Regards,

Hruday

0 HAYEON IM 5 months ago in reply to Hruday Kumar Mudireddy

Prodigy 20 points

HI Kumar,

This is Hayeon, it was my question. So, The filter should be placed for best performance, shouldn't it?

And Is the criterion for setting this value to achieve the lowest possible VSWR for impedance matching, or is it that TI's experimental results showed that the optimal value happens to be 8.66 + 140?

Regards,

Hayeon.

Amplifiers

Amplifiers forum

TRF0208-SEP: Matching and filter circuit with ADC12DJ5200-SEP