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YongseokJeon
Level 4
Level 4
Distributor - Changnam (South Korea)
50 replies posted 50 questions asked 25 replies posted

Hi, I have questions about ADC.
The CYT2B9 datasheet mentions the ADC total error specifications as below:

a.JPG

1. What does Total error mean?
Does total error mean that Quantization error, Offset error, Gain error, INL (Integral nonlinearity), and DNL (Differential nonlinearity) are all reflected?

2. What is the difference between A_TE and A_TEB?
If I use an ADC without offset and gain adjustments, will the ADC error have A_TEB (+/-12LSB)?

3. Please check below.
e.g. If the ADC input range is 5V, 1LSB=5V/4095 = 1.221mV
3-1. After offset and gain adjustment, the ADC has an error of +/-5LSB. i.e., +/-6.105mV
3-2. If I just use the ADC without performing offset and gain adjustment, the ADC has an error of +/-12LSB. i.e., +/-14.652mV

Thanks and Regards,
YS

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1 Solution
Shubham_D
Moderator
Moderator
Moderator
10 likes received First question asked 50 solutions authored

Hi @YongseokJeon ,

Q. What does Total error mean?
Does total error mean that Quantization error, Offset error, Gain error, INL (Integral nonlinearity), and DNL (Differential nonlinearity) are all reflected?

>>Yes, your understanding is correct. In the datasheet, the total error is specified with two SID parameters: SID109(A_TE) and SID109A(A_TEB). The total error consists of gain/offset and INL/DNL.



Q. What is the difference between A_TE and A_TEB?


A_TE:  The parameter used for "total error" after offset and gain adjustment at 12-bit resolution mode is the one that obtained after compressing  offset and gain errors.

A_TEB: The parameter used for "total error" before offset and gain adjustment at 12-bit resolution mode.


Q. If I use an ADC without offset and gain adjustments, will the ADC error have A_TEB (+/-12LSB)?
3. Please check below.
e.g. If the ADC input range is 5V, 1LSB=5V/4095 = 1.221mV
3-1. After offset and gain adjustment, the ADC has an error of +/-5LSB. i.e., +/-6.105mV
3-2. If I just use the ADC without performing offset and gain adjustment, the ADC has an error of +/-12LSB. i.e., +/-14.652mV

>> I am discussing with my internal team regarding this question. I will provide you with an update soon.

Thanks,
Shubham 

View solution in original post

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3 Replies
Shubham_D
Moderator
Moderator
Moderator
10 likes received First question asked 50 solutions authored

Hi @YongseokJeon ,

Q. What does Total error mean?
Does total error mean that Quantization error, Offset error, Gain error, INL (Integral nonlinearity), and DNL (Differential nonlinearity) are all reflected?

>>Yes, your understanding is correct. In the datasheet, the total error is specified with two SID parameters: SID109(A_TE) and SID109A(A_TEB). The total error consists of gain/offset and INL/DNL.



Q. What is the difference between A_TE and A_TEB?


A_TE:  The parameter used for "total error" after offset and gain adjustment at 12-bit resolution mode is the one that obtained after compressing  offset and gain errors.

A_TEB: The parameter used for "total error" before offset and gain adjustment at 12-bit resolution mode.


Q. If I use an ADC without offset and gain adjustments, will the ADC error have A_TEB (+/-12LSB)?
3. Please check below.
e.g. If the ADC input range is 5V, 1LSB=5V/4095 = 1.221mV
3-1. After offset and gain adjustment, the ADC has an error of +/-5LSB. i.e., +/-6.105mV
3-2. If I just use the ADC without performing offset and gain adjustment, the ADC has an error of +/-12LSB. i.e., +/-14.652mV

>> I am discussing with my internal team regarding this question. I will provide you with an update soon.

Thanks,
Shubham 

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YongseokJeon
Level 4
Level 4
Distributor - Changnam (South Korea)
50 replies posted 50 questions asked 25 replies posted

Hi, Shubham.
Thanks for your reply.

Please check if my understanding of Q3 is correct.

Thanks and Regards,
YS

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Shubham_D
Moderator
Moderator
Moderator
10 likes received First question asked 50 solutions authored

Hi @YongseokJeon ,

As you are aware of total errors in the minimum and maximum values outlined in the device-specific datasheet.

At the initial stages, prior to offset and gain adjustment, the ADC may have an error of (-12LSB to +12LSB), which corresponds to a range of (-14.652mV to +14.652mV). After offset and gain adjustment, this range narrows to (-5LSB to +5LSB). However, it is important to note that these are worst-case values and that the actual values may vary depending on external factors such as operating temperature, power supply voltage, and external interference or noise in the signal chain.


Thanks,
Shubham

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