Hi Eventually you will want multiple inputs to any chip like this. The more I/o the more crosstalk. Properly done, differential inputs will reduce your crosstalk quite a bit. You might as well debug that part of it now.
Bob > On Mar 27, 2017, at 9:05 AM, Attila Kinali <att...@kinali.ch> wrote: > > Hi, > > We (the group I am with and a group at TU Vienna) are currently designing > an ASIC (digital 65nm process) that will contain a TDC part. The TDC will > be a simple delay line TDC design using differential buffers, which we > expect to give us something in the order of 20ps of resolution (hopefully > better, but we will not know until we get post-layout simulation data). > We are loosely following the design CERN came up with for their new TDC > chip[1]. > > > Now, the TDC expects a differential input, but the system gets single-ended > pulses as input (50R coax input, level likely to be CMOS 3.3V, but level not > fixed yet, ie can be freely choosen). I can either convert these single-ended > signals into differential off-chip or on-chip. Unfortunately, I lack knowledge > and experience to judge either approach. The issues I see are: > > * Single-ended input in a chip might lead to shifting ground potential > on the chip and thus to measurment jitter. > * There are different architectures to preform the single-ended to > differential > conversion on-chip, but I have no clue which one to choose or even how > to judge them without extensive simulations for which we do not have the > time, know-how and probably not even the tools. > * Conversion to differential off-chip means another component off-chip > that might introduce additional delay uncertainty (our application is > very sensitive to that) and an unknown amount of jitter. > > My google foo has been so far not strong enough to find answers to these > questions. > > I would appreciate if someone could give me some hints in this matter > or tell me where I could find appropriate literature and maybe even > tell me whether I am missing anything. > > Thanks in advance > > Attila Kinali > > [1] > https://indico.cern.ch/event/228972/contributions/1539621/attachments/378552/526492/TDC_TWEPP_2013.pdf > > -- > It is upon moral qualities that a society is ultimately founded. All > the prosperity and technological sophistication in the world is of no > use without that foundation. > -- Miss Matheson, The Diamond Age, Neil Stephenson > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.