ADS62Pxx EVM capture parallel CMOS data

Hi,

There is not an option to purchase the EVM with the buffers installed for the CMOS output option from the ADC.  The only way the EVM is stocked for purchase is with the 0-ohm resistors installed for LVDS output to the Samtec connector.  To switch an EVM over to the CMOS output to the header posts, it would be necessary to unsolder the 0-ohm resistors and procure and solder down the buffer devices.

There is also the option to use the TSW1200 capture card on the Samtec connector in place of a logic analyzer, which is what the TSW1200 was made to do.  The TSW1200 can capture up to 64K samples from the ADS62P49 EVM and upload that to a PC for processing.  When the 64K sample size is not large enough for certain applications, then we have to use a logic analyzer ourselves. 

The TSW1200 also has the option to accept the DDR LVDS samples from the EVM and then output these samples in real time on CMOS output header posts on the TSW1200.  That is, the TSW1200 can take the function of those buffer chips on the ADC EVM, albeit at a higher overall cost, by converting the LVDS on the Samtec conenctor to CMOS samlpes on the posts on the TSW1200. 

Regards,

Richard P.

Thank you Richard.

I understand that the TSW1200 is a better and more quickly way to use this evaluation board, but the problem is that right now we don't have enough budget for both. The only option here is to use the Logic Analyzer.

Anyway, another question, all the ADS62PXXEVM are just right this one, right? But do you know any other adc's evaluation board with similar characteristics that has available some kind of headers out of the box, at least connectors that could be more easily connected with the logic analyzer than this SAMTEC connector here?

Although, do you have some pictures of an real board to realize how hard is to unsolder the 0-ohm resistors and solder again the COMS buffers?

Thank you very much for the quickly answer.

Regards,

Diogo Ribeiro

Hi,

All of our newer EVMs for this type of product will be set up by default for LVDS to the Samtec connector, even when the ADC itself has the option for CMOS or LVDS outputs, particularly when the sample rate could be as high as 250MHz.  This sample rate would be too fast for single ended CMOS switching.  The data converter tends to not have very strong single ended output buffers in order to limit switching noise on the device that might hurt AC performance on the analog side of the device.  You may notice in the datasheet for the ADS62P49 that there is a recommendation to *not* use the CMOS output option at the higher sample rates, even if the EVM were equipped for CMOS output. 

The portion of the EVM layout around the series 0-ohm resistors and buffers is copied below.  This information is also in the EVM User's Guide which is available on the web.  Removing the 0-ohm resistors is not too difficult, but for soldering down the buffer devices in their place you should consider the lead pitch of the buffer is 0.5mm, so that is a rather fine pitch for hand-soldering.  It requires solder equipment with a rather fine point, and a magnifying glass or microscope for inspecting the work.

Regards,

Richard P.