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# AD7606C-16 || Digital Data to Voltage Conversion

Category: Hardware

Hi Team,

I am using AD7606C-16 ADC IC for my receiver system.  I want to validate the ADC-received samples to my scope waveform. I am doubting what should I consider the value of Full Scale Range in the calculation formula.

Conversion formula:

Voltage= (Digital Data)* Full Scale Range / ((2^16)-1)

In the Oscilloscope I am seeing Vpp (measured at P wrt N I/p of ADC) is ~3.0Vpp

I am attaching the Digital Data, Pls suggest are the samples Ok. What Should I consider the Full Scale Range for my calculation?
CONVST Freq: 108KHz
Input Frequency: 27KHz

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• Hello  ,

I will contact the product owner and get back to you.

Regards,
Jo

• Hi Nathan,

• Hi Rehfi, Nathan,

We have observed that the ADC is set in Low Bandwidth Mode. To verify this we have carried out the gain-freq. response.

Below are our observations;

Datasheet Graph:

Our operating freq. is 27Khz, and the gain is nearly -3dB to this point.

• Hello  ,

Sorry for the late response. But upon reading your query, your main concern is "What Should I consider the Full Scale Range for my calculation?"

And to answer that, it would be depending on the voltage range selected. By default, it would be 10V.

Meanwhile, what is your question based on your last post in this thread? You have mentioned of using Low Bandwidth mode.

Thanks and regards,
Jo

• Hi Nathan,

To my last query;

" When measuring my ADC input at V1+ wrt GND I am observing ~1.4Vpp, similarly, at V1- wrt GND I am observing ~1.4Vpp. So, Input to ADC will be ~2.8Vpp.

But, while capturing from ADC (Digital Data, as you said) ~1.56Vpp is calculated.

I used the same formula of multiplying the digital data with 305.2 µV & took the min/max (assumed not hitting the max), I m observing ~1.74Vpp (less than 2.8Vpp) "

to this, we observed the ADC is configured in the low bandwidth mode. For this, we shared our observation (freq. vs gain) plot in the last thread.

• Ooooh... Good catch,  . I totally forgot about the filter.

Regards,

rehfi

• Hi arijeet,

this tool allows you to see the filter response vs frequency (among many other features) https://www.analog.com/media/en/engineering-tools/design-tools/ad7606x-software-model-2-1.zip

At 28kHz you should expect around 3.5dB attenuation, what seems to match approximately what you are seeing?

Regards,

Lluis.

• Hi Nathan, Lluis, Rehfi..

We tried writing the registers with the below-required value.

1. 0x03 - 88 (+/-5V differential range)
2. 0x04 - 88 (+/-5V differential range)

3. 0x05 - 88 (+/-5V differential range)

4. 0x06 - 88 (+/-5V differential range)

5. 0x07 - FF (setting high bandwidth)

6. 0x00 - 00 (referred from previous posts to set back to AC mode).

we are using a 96-clock cycle in total for writing the above data, but we observed the ADC is not coming out of register mode. & I am able to see the register data on DOUTA line(by probing)

Any suggestion on this.

• Hi Nathan, Lluis, Rehfi..

We tried writing the registers with the below-required value.

1. 0x03 - 88 (+/-5V differential range)
2. 0x04 - 88 (+/-5V differential range)

3. 0x05 - 88 (+/-5V differential range)

4. 0x06 - 88 (+/-5V differential range)

5. 0x07 - FF (setting high bandwidth)

6. 0x00 - 00 (referred from previous posts to set back to AC mode).

we are using a 96-clock cycle in total for writing the above data, but we observed the ADC is not coming out of register mode. & I am able to see the register data on DOUTA line(by probing)

Any suggestion on this.

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