DAC53004: Under-shoot on VOUT while setting output voltage

Aurelie Duval

Part Number: DAC53004

Hello,

I am using the DAC53004 to limit the current in a H-Bridge. The VOUT of the DAC (OUTA and OUTB) are connected to the gates of the MOSFETs and the FB (FBA and FBB) are connected to the sources.

I measured the differential voltage between E1 and E2 and I observed an "under-shoot". The red arrow is when the OUT of the DAC are enabled.

To see if the problem was coming from my circuit or from the DAC, I removed the DAC from the circuit and I connected OUT to FB directly.

This is the result:

Any reason why the DAC would do that?

Thanks for your help.

Best Regards

over 1 year ago

0 Illia Volkov over 1 year ago

TI__Intellectual 1595 points

Hello Duval,

Thank you for your question. I will come back with an answer over the weekend.

Thank you,

Illia Volkov

0 Illia Volkov over 1 year ago in reply to Illia Volkov

TI__Intellectual 1595 points

Hello Duval,

It is strange for me to see this behavior. Let me try to reproduce this in my lab and see if I have the same. In a mean time could you try to perform a similar experiment with a different device and see if you get similar results.

0 Aurelie Duval over 1 year ago in reply to Illia Volkov

Prodigy 150 points

Hello Volkov,

I unfortunately don't have a second device.

I will wait for your experiment then.

Thank you,

BestRegards,

Aurelie

0 Paul_Frost over 1 year ago in reply to Aurelie Duval

TI__Guru 52683 points

Thank you.

0 Illia Volkov over 1 year ago

TI__Intellectual 1595 points

hello Duval,

I am sorry, I still yet to received my parts to test. I should be able to test them tomorrow.

0 Aurelie Duval over 1 year ago in reply to Illia Volkov

Prodigy 150 points

Hello Illia,

Did you receive your parts? Have you had time to have a try?

Best Regards,

Aurelie

0 Illia Volkov over 1 year ago in reply to Aurelie Duval

TI__Intellectual 1595 points

Hello Aurelie,

I tried both configurations and I had a perfect line result and did not observe that behavior.

A few thoughts that I have that might help debugging:

1) The device might be faulty - try a different device

2) Try measuring the output directly at the pin of the DAC. Sometimes ling line can cause errors

3) Do you have a common ground?

4) What reference are you using? Your reference might be noisy. Try a decoupling cap or try using internal reference

Let me know if any of those steps helped.

Thank you,

Illia Volkov

0 Aurelie Duval over 1 year ago in reply to Illia Volkov

Prodigy 150 points

Hello Illia,

I've tried to measure the output directly at the pin of the DAC with a 0R resistor between the OUT and the FB and indeed I don't see the problem anymore.

I'll then assume that it was caused by the long cabling.

Thanks for your help.

Best Regards,

Aurelie

0 Illia Volkov over 1 year ago in reply to Aurelie Duval

TI__Intellectual 1595 points

Great,

Glad I was able to help, and I apologize for delayed responses.

Thank you,

Illia Volkov

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DAC53004: Under-shoot on VOUT while setting output voltage