An open source DAC is a worthy project. And there is demand for DACs. But can we make it a commodity prices? I think we'd have to do a full custom and make millions of them to make it cost-effective.
On Sat, Nov 3, 2012 at 6:17 PM, Troy Benjegerdes <[email protected]> wrote: > I'd rather design an open-source high-speed DAC silicon where > you have control over all the transistors and can just make > resistors exactly how you want them in silicon, instead of > trying to deal with the unknown black box of driver stuff > that's inside a digital I/O pins. > > If someone will commit to buying a lot of.. I don't know, > 10,000 DACs, then I can start working backwards from that > and tell you how much they will cost and when you can expect > to get them. > > What interface do you want on the digital side? I was thinking > a Gigabit ethernet DAC would be a pretty cool toy. ;) > > On Sat, Nov 03, 2012 at 09:17:41PM +0000, Jack Carroll wrote: > > To make a parallel DAC that's monotonic and doesn't have oversize steps > at the major bit carries, you need switches that introduce very small > voltage errors (less than 1/2 LSB worth of voltage at the MSB carry) or > else errors that are reproducible within 1/2 LSB from bit to bit. Generic > output pins from logic chips don't do that. I've done some designs of fast > parallel DACs with R/2R ladders and variant architectures, and getting the > right switches and a stable reference rail is the biggest challenge. Doing > it at a high update rate just makes everything tougher, and building it out > of separate switch chips and resistor arrays just makes everything harder, > because the physical size of the PCB interconnects between components adds > stray inductances and capacitances. If you can buy the DACs and line > drivers, it's a lot easier. > > > > Jack Carroll > > > > ----- Original Message ----- > > From: "Timothy Normand Miller" <[email protected]> > > To: "Ing. Daniel Rozsny??" <[email protected]> > > Cc: [email protected] > > Sent: Wednesday, October 31, 2012 9:48:35 AM > > Subject: Re: [Open-graphics] The next OGA card? > > > > > > > > Actually, if we have lots of I/Os to spare, we might be able to do > > analog video using a resistor network and a low-pass filter. Someone > > with a better EE background could answer that. > > _______________________________________________ > > Open-graphics mailing list > > [email protected] > > http://lists.duskglow.com/mailman/listinfo/open-graphics > > List service provided by Duskglow Consulting, LLC (www.duskglow.com) > -- Timothy Normand Miller, PhD Assistant Professor of Computer Science, Binghamton University http://www.cs.binghamton.edu/~millerti/<http://www.cse.ohio-state.edu/~millerti> Open Graphics Project
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