ADC08DJ3200EVM: Lowest signal frequency for calibration

Emir Karamehmedovic

Part Number: ADC08DJ3200EVM

I am trying to use ADC08DJ3200EVM. In the Users Guide of ADCxxDJxx00, it is recommended to use 1910 MHz signal in the calibration procedure. Is it possible to use a lower frequency signal for calibration, and if not calibrated, is it still possible to use the ADC EVM?

over 2 years ago

0 Neeraj Gill over 2 years ago

TI__Mastermind 20541 points

Hi,

For foreground calibration the input signal is not required. So it does not matter what its frequency is. The only limitation is when performing foreground offset calibration there should no signal near DC or Fs/2.

Regards,

Neeraj

+1 Emir Karamehmedovic over 2 years ago in reply to Neeraj Gill

Prodigy 100 points

Hi Neeraj,

thanks! Is e.g. a 5-50MHz signal considered close to DC for a GB/s sampling unit?

0 Neeraj Gill over 2 years ago in reply to Emir Karamehmedovic

TI__Mastermind 20541 points

Hi Emir,

Below 1MHz would be considered close to DC. 5-50MHz shoud be fine.

Regards,

Neeraj

0 Emir Karamehmedovic over 2 years ago in reply to Neeraj Gill

Prodigy 100 points

Hi Neeraj,

Does the ADC08DJ3200EVM automatically remove any offset of the input signal? I would like to connect a differential signal - on the scope the + and - of the signal range from 0.6-1.4V but are within 800mVpp as differential signal. Is it OK to connect that to the differential inputs? Will the common mode voltage be subtracted? The datasheet of the ADC states that max input common mode is 100mV. Also, do I need to configure the board to differential input or it automatically detects whether the input is SE or DIFF?

0 Rob Reeder over 2 years ago in reply to Emir Karamehmedovic

TI__Mastermind 39340 points

Hi Emir,

Sorry for the delay. Yes, you need to configure the EVM to use a differential signal. Please use DC blocking capacitors and the common mode DC voltage will be fine. Otherwise, if you plan to connect a signal or pulse generator to the EVM and DC couple. Then you must maintain the DC common mode between the two devices in order for the ADC to sample appropriately.

Regards,

Rob

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ADC08DJ3200EVM: Lowest signal frequency for calibration