TLV320ADC3140: Swift excessive Input

Kuramochi Tadahiko

Guru 28715 points

Part Number: TLV320ADC3140

Hi,

My customer is evaluating TLV320ADC3140 and abnormal data is outputted when swift excessive voltage is inputted.

Output data is normal when voltage is not swift as following attached.

TLV320ADC3140.xlsx

This symptom appears in spite of input channel port and zero data is outputted when swift excessive voltage is inputted into multiple channels simultaneously.

They are using only PGA function on related level adjusting(not using digital volume, auto gain).

I have two questions.

・Is this behavior caused by any function of this ADC?

・Is there any hided register to find this condition?

Best Regards,

Kuramochi

over 4 years ago

0 Collin Wells over 4 years ago

TI__Guru 62085 points

Hello Kuramochi,

Can you also show what the input voltage signal looks like, or provide the voltage levels and ramp/slew rates so we can better conceptualize what is being applied to the ADC input?

0 Kuramochi Tadahiko over 4 years ago in reply to Collin Wells

Guru 28715 points

Collin-san,

Thank you for your reply.

I attach the waveform.

The phenomenon is not occurred when sine wave.

Is this any protection function?

Best Regards,

Kuramochi

0 Kuramochi Tadahiko over 4 years ago in reply to Kuramochi Tadahiko

Guru 28715 points

Collin-san,

I'm sorry to trouble you.

How is this progress?

Best Regards,

Kuramochi

0 PedroGelabert over 4 years ago in reply to Kuramochi Tadahiko

TI__Expert 6995 points

Kuramochi-san,

The data sheet specifies a maximum input voltage, as follows:

differential input full-scale AC signal voltage to be 2Vrms
single-ended input full-scale AC signal voltage to be 1Vrms

The plot shows a 3.3V signal swing, so the signal will be clipped at the ADC input. Please reduce the signal swing to within data sheet specs.

Best regards,
Pedro

0 Kuramochi Tadahiko over 4 years ago in reply to PedroGelabert

Guru 28715 points

Pedro-san,

Thank you for your information.

I understand you answer.

This behavior is not intended, right?

Best Regards,

Kuramochi

0 Collin Wells over 4 years ago in reply to Kuramochi Tadahiko

TI__Guru 62085 points

Hi Kuramochi,

To Pedro-san's point, the maximum input voltage of the ADC is being exceeded by this input voltage. Therefore the results will likely be unexpected.

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TLV320ADC3140: Swift excessive Input