AD9951 Amplitude

Hi,

I removed 0Ω resistance after transformer(DIFF ⇒ SE), then each output of AD9951 shows 500mVpp before Trans and  1Vpp after Trans.

Best Regards,

ttd

PDF

Hi,

I also find this somehow mysterious. Will have to setup a bench test next week for us to verify this one. We're still waiting for some components to arrive. 

Also can you verify the new output given on your latest comment? It seems like the one you sent is just the same as the first one. 

Regards,

Jules

Hi Jules,

Thank you for your reply.

I'm looking forward to see bench test.

>Also can you verify the new output given on your latest comment? It seems like the one you sent >is just the same as the first one. 

⇒I attached pdf on my latest comment and it's page 2 have removed 0Ω and waveform.

Best Regards,

ttd

Hello,

Thank you for your response. Apologies for overlooking the 2nd page.

Anyway, just want to ask the output after the filter? So we can also verify it on my end. 

All the best,

Jules

Hi Jules,

output after the filter shows about 290mVpp with 51Ω after trans.

See green waveform on page1.

Best Regards,

ttd

Hi,

Apologies for not specifying. I was referring to the one after you removed the 0 ohm. 

Regards,

Jules 

Hi Jules,

I updated three waveforms,

Could you check it?

 ・original Circuit(0Ω)

 ・Fixed Circuit 1(51Ω)

 ・Fixed Circuit 2(R1168=No Mount)

Best Regards

ttd

PDF

Hi Jules,

Is there any update so far?

Best Regards,

ttd

Hi Jules,

Is there any update so far?

Best Regards,

ttd

Hi there,

Apologies for responding late. Still waiting for the components to arrive. I will send you an update once we will start the bench test. 

All the best,

Jules

Hi Jules,

Thank you for your reply.

I understand your situation.

Best Regards,

ttd

Hi Jules,

Do you have any update so far about your test bench?

Best Regards,

ttd

Hi ttd,

It's been a while. Apologies for the late update. The parts will arrive this week. As soon as it arrives, I will give you another update once I commence the bench test.

All the best,

Jules

Hi ttd ,

I will now start the bench test. I will let you know once I get some results and will get back to you.

All the best,

Jules

Hi Jules,

Thank you for your reply.

I'm looking forward to see your resules.

Best Regards,

ttd

Hi ttd ,

Upon bench testing, we were able to generate these waveforms.

For reference, we were using this circuit (AD9954 Eval Board) which is somehow similar to the circuit you have given.

For the full schematic diagram of AD9954 Eval Board, here the link.

Based on this schematic diagram, we measured to different points.

Point A = Pin 1

Point B = Pin 3

Point C = Pin J2

Point D = Pin J1

Using jumpers to pins 1 and 4, here’s the output of J2 (unfiltered output)

Channel 1 is Pin 3

Channel 2 is Pin 1

Channel 3 is J2

Using jumpers to pins 1 and 2, here’s the output of J1 (filtered output)

Channel 1 is Pin 3

Channel 2 is Pin 1

Channel 3 is J1

And comparing these results from your original circuit to the bench test we did today, it is somehow similar or approximately having close values. To answer your question, yes, the amplitude is similar to the results of the bench test that we did today. Your initial results are the expected amplitude that you should also be getting.

For comparison here’s the results of our bench test today:

All the best,

Jules

Hi Jules,

Thank you for your bench test.

It seems like my results.

I assumed 50Ωx10mA = 500mVpp, but the level is actually low. I feel that it is less than the original 10mA full scale depending on the load, please tell me the reason. If the amplitude is not exactly determined, it is very difficult to estimate the amplitude before board development.

Best Regards,

ttd

Hi ttd ,

Just want to ask the value of your Rset?

Regards,

Jules

Hi Jules,

DAC Rset=3.92kΩ for 10mA.

Best Regards,

ttd