ADC12DJ2700: FS_RANGE_A(B) Questions about Field Descriptions

cafain

Part Number: ADC12DJ2700

Hi, Staff

There is a register that sets the full-scale value of FS_RANGE_A and FS_RANGE_B.
(Datasheet SLVSEH9A Table59, and Table60)

When the set value is 0xA000h (40960d), it is FS=800mVpp full scale.
For example, if you set the value to 0xA1000h, what is the full scale Voltage? (810mVpp?)

In other words,
When increasing the value by 100d, does the full scale value increase linearly?
What is the amount of full scale to increase?

If not increasing linearly, how much linearity is guaranteed?

best regards
cafain

over 5 years ago

0 Neeraj Gill over 5 years ago

TI__Mastermind 20541 points

Hi Cafain,

Please use the following formula to calculate the full scale range.

VFs = (Code -8192)* 560/57343 +480mV. Code is the decimal value programmed in register FS_RANGE_A or FS_RANGE_B respectively.

Regards,

Neeraj

0 cafain over 5 years ago in reply to Neeraj Gill

Mastermind 6775 points

Hello, Neeraj -san

Thank you for your urgent reply.

When the register value is 0xFFFF, VF will be calculated to be 1040 mV.
Table 59 says that VF=1000 mV pp, but the difference of 40 mV is
Should I consider it as a calculation error?

best regards

cafain

0 Neeraj Gill over 5 years ago in reply to cafain

TI__Mastermind 20541 points

Hi Cafain,

Please use the value from the table in section 6.5 of the datasheet.

Regards,

Neeraj

0 cafain over 5 years ago in reply to Neeraj Gill

Mastermind 6775 points

Hello Neeraj san

I overlooked the contents of the data sheet.
Excuse me.
Thank you very much.

Regards

cafain

0 cafain over 5 years ago in reply to cafain

Mastermind 6775 points

Hello, Neeraj san

Let me ask you an additional question.

Is full-scale adjustment completely digital?

If the full scale is changed in an analog manner by setting the DA converter in the ADC12DJ2700, would it be affected by the DNL and INL of the DA converter and the linearity of the accompanying analog circuit?

best regards

cafain

0 Neeraj Gill over 5 years ago in reply to cafain

TI__Mastermind 20541 points

Hi Cafain-san,

1. The full scale is an analog setting. When you change the Full scale register value the reference to the ADC is changing in voltage.

2. Yes your assumption is correct, the DNL and INL will be different for different full scale values.

Regards,

Neeraj

0 cafain over 5 years ago in reply to Neeraj Gill

Mastermind 6775 points

Hello Neeraj san

I understand that FS is changed by adjusting the reference electric power.

Is it possible to provide DNL and INL data when FS=1040mV?
*1040mV is not specified in order to understand the fluctuation of DNL and INL. For example, 900mVpp is fine.

Regards

cafain

0 Neeraj Gill over 5 years ago in reply to cafain

TI__Mastermind 20541 points

Hi Cafain,

The datasheet has the INL and DNL at 800mVpp. The INL and DNL should not change significantly at 1040mV or 900mVpp.

Regards,

Neeraj

0 cafain over 5 years ago in reply to Neeraj Gill

Mastermind 6775 points

Hello Neeraj san

Evaluate with reference to the comment that there is no big difference in specifications.

Regards

cafain

0 Neeraj Gill over 5 years ago in reply to cafain

TI__Mastermind 20541 points

Hi Cafain,

Yes there shouldn't be a big difference in performance.

Regards,

Neeraj

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ADC12DJ2700: FS_RANGE_A(B) Questions about Field Descriptions