THS4531: How to output differential signals with single-ended inputs

Looks like you have a TINA file, probe your input summing junction pins and see if they are in range. Also you should match impedances on the upper side with 100pF and whatever your source looks like. 

You can probably do this with a single 5V supply, the FDA will also level shift a ground centered swing up if the source can sink that level shift current. 

Hi Michael，

Thank you for your answer.

At first, I thought the input voltage was -5~+5V, I could get a differential signal of 0-3V, as shown below.

But I was wrong, the real input voltage was 0-5V, can I get the same waveforms like the above figure?

I'm not familiar with the specs of the THS4531, can you help me?

Best Regards,

Boyuan

If you have that TINA file, attaching that would be helpful, 

Hi Michael，

This is my TINA file, thank you for your help.4214.THS4531.TSC

Thanks, I poked around on this in the attached, 

made some deadend tests, but eventually, your 0V to 3V input is absolutely clipping at the outputs - reset your supplies and Vocm and gain until it does not, 

Updated TINA file below, 

THS4531 single to diff test cases.docx

Original THS4531 gain of 0.5.TSC

Hi Michael，

Thank you for your answer!

I have made some changes according your answer.

I use THS4501 to replace THS4531, the supply can be +/-5V. 

The updated TINA file is as follows.

Please help me to check if it is correct. (The differential signal I want to get is 0-3V.)

Regards,

Boyuan

ADTLIC.TSC

well there is a lot going on up to the FDA here, but yes, the FDA is producing an in range output of 0 to 3V on each output -that is in fact 6Vpp as the two outputs flip phase back and forth

The signal is very slow for the THS4501, you might look at the 

THS4131 if non-RR output is ok

THS4561 if you want to stick with +/-5V

If your eventual need is +/-1.5V around a 1.5Vcm at the ADC inputs, the th4531 RR output should be able to do this directly with just a 3.3V single supply - if you really want to swing 0V on the output pin, RRout is not linear to 0V, but using the LM7705 fixes that. 

Hi Michael,

Using the LM7705 can fix the signal distortion, but the input voltages +/-1.5V seem to exceed the range of input voltage of THS4531.

Can you tell me the signal speed of the THS4501, and what the means about non-RR output, I am not familiar with the FDA.

Lastly, can you recommend a high-speed FDA with a +/-5V power supply? It will output a 0-3V differential signal to the 28377D DSP.

Thanks,

Boyuan

Thank you for your answer! It will help me to design the FDA circuit.

Best Regards,

Boyuan