4DSP Support Forum

Products => FMC Products => FMC150 => Topic started by: jwdonal on June 04, 2014, 10:01 PM

Title: FMC151 DAC 'C' output inverted
Post by: jwdonal on June 04, 2014, 10:01 PM

Are there any known-issues/errata with the FMC151 DAC outputs?  We are seeing that any waveform that we output on DAC 'C' is inverted from the original waveform that we send. However, the waveform on DAC output 'D' is correct (i.e. not inverted).

                                 DAC 'C' ==> O-scope ==> inverted
Same Waveform ==<
                                 DAC 'D' ==> O-scope ==> _not_ inverted

It seems as if somehow the differential P/N pairs were hooked up incorrectly on the board for DAC 'C'.

Running the identical FPGA design and FMC150App with the FMC150 card does not have this issue. So therefore it has to be an issue with the FMC151.

Title: Re: FMC151 DAC 'C' output inverted
Post by: peter on June 04, 2014, 10:30 PM

Hi Jonathon,


The P/N pair of output C is indeed inverted. This is noted in section 4.5 of the User Manual.


Best regards,
Peter

Title: Re: FMC151 DAC 'C' output inverted
Post by: dpryan on June 05, 2014, 02:43 PM

Gotta love "features" like this...


Edit: It would be cool if you somehow indicated this on the block diagram (Figure 1). Like an inversion bubble on the channel C output.

Title: Re: FMC151 DAC 'C' output inverted
Post by: arnaudNL on June 13, 2014, 08:08 AM

This topic is being closed because the issue is considered as resolved by 4DSP. Feel free to create a new topic for any further inquiries.