ADC12DL3200EVM: Series resistor

Nandini Muralidharan

Intellectual 750 points

Part Number: ADC12DL3200EVM

Tool/software:

Hi,

What is the purpose of the series resistors used in reference design?

How it needs to be calculated?

Thanks

6 months ago

0 Geoff Roth 6 months ago

TI__Expert 4480 points

Hi,

These are just to slow down the edge coming out the level translator. The R is based on the C of your line and the edge rate you want to slow it down to.

Regards,

Geoff

0 Nandini Muralidharan 6 months ago in reply to Geoff Roth

Intellectual 750 points

Hi Geoff,

In our design we plan to connect these signals directly from ADC to FPGA. In such case, are these series resistors required?

If yes, is there any calculation you can point me to choose these resistances?

We will be connecting CALSTAT, CALTRIG and PD also interfaced with FPGA directly. Are similar resistors required on those nets as well?

0 Geoff Roth 6 months ago in reply to Nandini Muralidharan

TI__Expert 4480 points

Hi Nandini,

No, you do not have to add series resistors. They were put in just in case we needed to adjust the output rise time by limiting the current.

Regards,

Geoff

0 Nandini Muralidharan 6 months ago in reply to Geoff Roth

Intellectual 750 points

Hi Geoff,

I plan to add a series 0-ohm placeholder just in case we encounter the need to tune the rise time.

Hope that is ok to do without any adverse effects..

Thanks

Nandini

0 Rob Reeder 6 months ago in reply to Nandini Muralidharan

TI__Mastermind 30880 points

Hi Nandini,

Adding the 0ohm resistors should not be an issue.

Regards,

Rob

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ADC12DL3200EVM: Series resistor