TLV5620: Output error

Kaustubh Kulkarni

Part Number: TLV5620

Hello all,

A student is working on the TLV5620 and he is facing the following problem,

" The part is outputting non zero voltage on entering 0 code and the output doesn't change until about value 50 when in normal mode and 25 when in double range mode. I have a 10k pulldown on the dac outputs as per the datasheet and also buffer the outputs so no excessive currents are drawn. VDD and REFs are both 5v. "

I think, according to the datasheet recommended VDD is 3.3 and VREF is VDD - 1.5. Could it be this problem or anything else.

Could anyone help me with this.

thank you in advance.

over 8 years ago

0 Kaustubh Kulkarni over 8 years ago

TI__Intellectual 1040 points

Hello,

Could anyone help me to answer this ?

Thank you.

0 Uttam Sahu over 8 years ago in reply to Kaustubh Kulkarni

TI__Genius 14220 points

Hi Kaustubh,

Sorry for the delay in responding. The VREF doesn't seem to be the issue. Could you please send a scope capture of the digital data? Looks like some kind of masking or shifting happening. We can take this conversation over mail if you want so that you can share schematics etc.

Regards,
Uttam Sahu
Applications Engineer, Precision DACs

0 Uttam Sahu over 8 years ago in reply to Uttam Sahu

TI__Genius 14220 points

Hi Kaustubh,

Is there any update on this?

Regards,
Uttam

0 Kaustubh Kulkarni over 8 years ago in reply to Uttam Sahu

TI__Intellectual 1040 points

Hi Uttam,

Sorry, I didn't answer to your reply.
I also didn't hear back from him yet. So, I will let you know if I have some news.
Thank you

0 Paul_Frost over 8 years ago in reply to Kaustubh Kulkarni

TI__Guru 54583 points

Hi Kaustubh,

I think the issue could be caused by two factors. Firstly, the VREF value is too large and is violating the recommended maximum. The reference should not be more than VDD-1.5V to ensure operation.

In addition, you should consider the zero-scale error of the device. This device has a positive zero-scale error, meaning that the device will have non-linear operation until the ideal DAC output exceeds the zero-scale error. This video describes this at about 3:30 minutes.

I would ensure that you change the reference first, then try the test again.

Thanks,

Paul

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TLV5620: Output error