This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TINA/Spice/THS4509: THS4509 Simulation data

Part Number: THS4509
Other Parts Discussed in Thread: TINA-TI, ,

Tool/software: TINA-TI or Spice Models

Hi

I am designing differential signal amp using THS4509.

Input signals are sine wave,400mVpp, 76kHz.

I have simulation result using TINA as below.

When I tested using THS4509EVM, Waveform is different with simulation.

CH2, CH4: INPUT CH1: OUTPUT

What is reason? Why output voltage is dc4.7V??

 Do you have any idea??

  • Hi Mason,

    What is the THS4509EVM supply voltage you are operating on? Also, can you confirm whether the Ch1, Ch2 and Ch4 of the oscilloscope are set to 50-ohm inputs? For differential input THS4509EVM setup, can you confirm whether the R12 is open or do not populate (DNP)? Also, I would recommend the R1 and R2 to be 100-ohms as shown in the below setup.

    One thing to keep in mind is that the ADT1-1WT output balun is only rated to a minimum frequency of 400kHz. As a result, you might see a lot of attenuation due to the output transformer at 76kHz input frequency. You could try uninstalling this balun and use an external output balun like the ZFSCJ-2-2 instead to see if the output signal is restored. Also, the output signal is attenuated by -15.2dB on the THS4509EVM due to the series output matching resistors - two 86.6ohms and 69.8ohms in parallel with 150-ohms of the transformer secondary. As a result, you can try setting the oscilloscope vertical display to 50mV/div or lower and see if there is any ac signal riding over the 4.7V DC.

    Best Regards,

    Rohit