ADC12DJ5200RF: Multiple ADC12DJ5200 ICs power sequencing

Harshitha Reddy

Prodigy 80 points

Part Number: ADC12DJ5200RF

Hi,

In my design I am using 3 ADCs ADC12DJ5200RF ICs, I have a query on Power supply sequencing of multiple ADCs.

As per the ADC datasheet recommendations,

Vx11 (Analog and Digital supplies) regulator is enabled after the VA19 supply is good
VA11 and VD11 are derived from a common 1.1-V regulator

Please refer attached Power scheme. As per the attached Power Sequencing 1V9 power good of adc1 will be connected to Analog 1V1 regulator enable of adc1 IC, similarly for adc1 and adc2 also.

but as Digital 1V1 supply is combined for all the ADCs, when should I enable Digital 1V1 supply regulator, should I use oring logic of 1V9 power enables or should I use saperate LDOs for Digital supply.

Is the attached powering scheme for ADCs recommended?

Please guide us.

over 2 years ago

0 Rob Reeder over 2 years ago

TI__Mastermind 42200 points

Hi Harshitha,

The power tree shown above will work fine. Please follow the recommendations as per the datasheet in the initial ADC bring-up.

Regards,

Rob

0 Harshitha Reddy over 2 years ago

Prodigy 80 points

Hello,

Thank you for your response.

In datasheet it is recommended that

Vx11 (Analog and Digital supplies) regulator is enabled after the VA19 supply is good.
VA11 and VD11 are derived from a common 1.1-V regulator.

Now, using this power scheme (refer below image) when I should enable Digital 1V1 Supply. Can I use Oring of All ADCs 1V9 power good signals to enable Digital 1V1 Supply pin or ADC1 1.9V power good shall I Connect to Digital 1V1 Supply enable pin?

0 Rob Reeder over 2 years ago in reply to Harshitha Reddy

TI__Mastermind 42200 points

Hi Harshitha,

Please use the power good signals to enable the digital 1V1 supply pin once the all the ADCs 1V9 is good.

Regards,

Rob

0 Harshitha Reddy over 2 years ago in reply to Rob Reeder

Prodigy 80 points

Hi Reeder,

I understood. Thank you for your response.

Once all the 1V9 rails is good then shall I enable both Digital 1V1 Supply and Analog 1V1 Supply enable pins together, is it recommended?

or only Digital 1V1 Supply should be enable and Analog 1V1 supply enable use same as shown in the previous attachment?

0 Rob Reeder over 2 years ago in reply to Harshitha Reddy

TI__Mastermind 42200 points

HI Harshitha,

Even tho you have multiple ADCs and some power domains are tied together. Still the recommendation is to follow the datasheet power sequence recommendations found in the datasheet.

Regards,

Rob

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ADC12DJ5200RF: Multiple ADC12DJ5200 ICs power sequencing