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.
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