ADS9815: ads9815 ground

Chen Alex1

Expert 2965 points

Part Number: ADS9815

Tool/software:

hi Sir

If the ADS9815 have the Different between AGND & DGND

according to Datasheet Figure 8-4，GND &IOGND connect to AGND together.

But the Figure 8-1 IOGND Is connect to DGND，

which one is correct?

and Thermail pad should connect to which GND? IOGND or AGND

Thanks

3 months ago

0 Samiha Sharif 3 months ago

TI__Expert 6231 points

Hi Chen,

Thanks for your question. IOGND, GND and thermal pad may all be connected to the same GND plane. No need for separate AGND and DGND. In the Table 4-1, we actually updated all the IOGND and GND pins to have the same name: GND. We will update these graphics to also show GND!

Best regards,

Samiha

0 Chen Alex1 3 months ago in reply to Samiha Sharif

Expert 2965 points

hi Samiha

ADI/ Pin driver is in front of the ADS9815, how about the ADC ground should connect to? connect to IOGND & thermal gnd ?

Thanks

0 Samiha Sharif 3 months ago in reply to Chen Alex1

TI__Expert 6231 points

Hi Chen,

Which ADI pin driver are you using? ADATE318? Let me know if you need a schematic review. The AGND might be a good choice as it is cleaner and has no switching noise.

Best regards,

Samiha

0 Chen Alex1 3 months ago in reply to Samiha Sharif

Expert 2965 points

hi Samiha

Please refer to below figure, due to system have the different Ground between AGND & TGND

may i know the ADS9815 should connect to AGND or FPGA DGND

Thanks, we have two solution ,another is ADI /AD7606.

AD7606 separate the AGND and DGND

0 Samiha Sharif 3 months ago in reply to Samiha Sharif

TI__Expert 6231 points

Hi Chen,

You may connect the AGND to ADS9815. ADS9815 has better total unadjusted error and solution size compared to AD7606.

Best regards,

Samiha

0 Chen Alex1 3 months ago in reply to Samiha Sharif

Expert 2965 points

HI Samiha

AD7606 need to separate AGND and DGND, TI don't?

0 Samiha Sharif 3 months ago in reply to Chen Alex1

TI__Expert 6231 points

Hi Chen,

Our ground is consolidated into one plane internally.

Best regards,

Samiha

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ADS9815: ads9815 ground