ADC3669: LVDS compatibility problem when connected to TSWDC155EVM

H.T

Part Number: ADC3669
Other Parts Discussed in Thread: TSWDC155EVM

Tool/software:

According to your application note, the ADC3669 eval boards can be connected to TSWDC155EVM board for evaluation. However, i found the ADC3669 LVDS output is not compatible to the Artix7 FPGA on TSWDC155EVM board. the differiential output voltage of ADC3669 doesn't match to differential input voltage of Artix7 FPGA. Please see below pictures. will it cause data corruption or physical damage to the chip?

Artix7 LVDS spec

ADC3669 LVDS spec

10 months ago

0 Rob Reeder 10 months ago

TI__Mastermind 45670 points

Hi,

This interface works just fine. What specification are you particularly worried about?

Regards,

Rob

0 H.T 10 months ago in reply to Rob Reeder

Prodigy 50 points

The typical differential output voltage of ADC3669 is 700mVpp. However, the maximum differential input voltage of Artix 7 FPGA is 600 mV only. will it cause data corruption or phyical damage at Artix 7 side?

0 Rob Reeder 10 months ago in reply to H.T

TI__Mastermind 45670 points

Hi HT,

On the Artix7 side, this is showing the input swing required as the voltage changes from min to max.

Its not reflecting the max swing that pin can handle.

The ADC3669 output LVDS levels are well within the abs max of these specific Artix pins.

Therefore, no damage is caused.

Regards,

Rob

0 H.T 10 months ago in reply to Rob Reeder

Prodigy 50 points

Thanks for the reply. As the ADC3669 ouput diffiential voltage is higher than the maxium input diffirential voltage(operation) of Artix7, will it cause logic error at recevier side?

0 Rob Reeder 10 months ago in reply to H.T

TI__Mastermind 45670 points

No, it does not cause errors on the RX side.

Both of these boards work together and we have proven this out over all modes and configurations.

Regards,

Rob

0 H.T 9 months ago in reply to Rob Reeder

Prodigy 50 points

above are LVDS output single-ended waveform and differential waveform. the ADC3669 datasheet says the differiential output peak-to-peak is maximum 850mv, is the 850mv 1x Vod or 2x Vod in above diagram?

0 Rob Reeder 9 months ago in reply to H.T

TI__Mastermind 45670 points

Hi HT,

Referring to the differential waveform diagram. 850mVpp would refer to Vodx2.

Regards,

Rob

PS - Maybe this diagram will help understand DIFF signals:

Data converters

Data converters forum

ADC3669: LVDS compatibility problem when connected to TSWDC155EVM