ADC12DJ3200EVM: need of 1k resistor in series with NCO and OVR signals

LALIT VERMA

Part Number: ADC12DJ3200EVM

Hi TI,

Can I know the reason behind using the 1k resistor in series with NCO and OVR signals at output of buffer?

Since we also using the level shifter in our application, thats why need to know whether we also need to place these 1k resistors in series with NCO or OVR signals or not?

An early response will be highly appreciated.

Thanks,

Lalit

over 4 years ago

0 Yusuf%20Agoro over 4 years ago

TI__Expert 4880 points

Hi Lalit,

We are taking a look at your question and will get back to you asap.

Yusuf

0 LALIT VERMA over 4 years ago in reply to Yusuf%20Agoro

Expert 1635 points

Hi Yusuf ,

Please update on this.

Thanks,

Lalit

0 Neeraj Gill over 4 years ago in reply to LALIT VERMA

TI__Mastermind 20541 points

Hi Lalit,

Are you connecting NCO pins and OVR pins the FPGA?

Can you please share the section of the schematic and explain how these pins are connected?

Regards,

Neeraj

0 LALIT VERMA over 4 years ago in reply to Neeraj Gill

Expert 1635 points

Hi Neeraj,

Yes we are connecting the NCO and OVR pins of ADC to FPGA.

Below is the schematic image of level translator showing the NCO and OVR signals.

A side of level translator is connected to ADC and B side is connected to FPGA through FMC connector.

We have not used any 1k resistor in our design but in TI Eval board 1k resistors are used in series with NCO and OVR signals. We are not able to understand the reason behind using 1k resistors.

Do we also need to use 1k resistors in our design?

An early response will be highly appreciated.

Thanks,

Lalit

0 Neeraj Gill over 4 years ago in reply to LALIT VERMA

TI__Mastermind 20541 points

Hi Lalit,

You don't need 1k resistors. This was done on the EVM because we have two ways to control NCO pins on the ADC with the jumpers and with the FTDI chip. The 1k act as the separation between two control methods.

Regards,

Neeraj

0 LALIT VERMA over 4 years ago in reply to Neeraj Gill

Expert 1635 points

Hi Neeraj,

Thanks for the useful info.

Thanks,

Lalit

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ADC12DJ3200EVM: need of 1k resistor in series with NCO and OVR signals