ADS7049-Q1: OCR register size, max/min offset that can be applied

Gerry Griffin

Prodigy 20 points

Part Number: ADS7049-Q1

Hi,

Our Radiation SEE tests show that the OCR register is susceptiple to SEUs (bit flips).

Our design does not use this feature, we do not use:
8.4.1.2 Offset Calibration During Normal Operation

Part of the problem for us is detection of OCR register bit upsets, as it is not possible to
read this register.

We would like to deteremine the full impact of this register on the ADC converted data,
would it be possible for you to imform us how many bits are in this register and the
maximum offset that can be applied to the converted data (positive or negative) ?

Many thanks,

Gerry

over 3 years ago

0 Aaron Estrada over 3 years ago

TI__Mastermind 22950 points

Hi Gerry,

Just to clarify some things... Are you not using the offset calibration feature at all? You state that you are not using the calibration during normal operation but are you using the offset calibration on power up?

If I understand correctly, you are worried that if the OCR register is affected and has some bits flipped, then this will affect the conversion data. Is my understanding correct? While, I do not immediately know the number of bits the OCR register can contain but I will discuss this with the team and get back to you shortly.

Regards,

Aaron Estrada

0 Gerry Griffin over 3 years ago in reply to Aaron Estrada

Prodigy 20 points

Hi Aaron,

Have you had a chance to discuss this with the team?

We are not using the calibration feature at all, at power-up or normal operation.

We would like to work out the max. offset that can be added/subtracted to/from the converted data

due to OCR bit-flips. Are all of the OCR bits applied to the converted data, is the offset that can be applied limited ?

Thanks,

Gerry.

0 Aaron Estrada over 3 years ago in reply to Gerry Griffin

TI__Mastermind 22950 points

Hi Gerry,

I am still awaiting a response from the team. I apologize for the delay and appreciate your patience. I will update you as soon as possible.

Regards,

Aaron Estrada

0 Gerry Griffin over 3 years ago in reply to Aaron Estrada

Prodigy 20 points

Hi Aaron,

We are in the final stages of completing our Radiation Reliability Analysis, and it would really help us to have this data.

Thanks,

Gerry.

0 Aaron Estrada over 3 years ago in reply to Gerry Griffin

TI__Mastermind 22950 points

Hi Gerry,

Understood. This is an older device and it is taking us a bit longer than originally anticipated to pull the information needed. I have not forgotten about this and continue to work with the team to get the information you need.

Regards,
Aaron Estrada

0 Aaron Estrada over 3 years ago in reply to Aaron Estrada

TI__Mastermind 22950 points

Hi Gerry,

The team has confirmed that the offset calibration register is 11-bits but we are still trying to determine the min/max offset that can be applied. 11-bit seems a little excessive for a 12-bit device so we are trying to confirm.

Regards,
Aaron Estrada

0 Collin Wells over 3 years ago in reply to Aaron Estrada

TI__Guru 63205 points

Hi Gerry,

It took a little bit for this one to make it's way to us, but we have a team that helps out with radiation testing of our devices and we'd be very interested to learn more about your results.

We'll also work with Aaron to determine the required information. I will reach out to your e-mail directly.

0 Collin Wells over 3 years ago in reply to Collin Wells

TI__Guru 63205 points

To close the loop on the forum, the min/max applicable offset, the effective offset correction range is 9-bits (+/- 256 LSB).

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ADS7049-Q1: OCR register size, max/min offset that can be applied