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Cheap 12 bit DAC and ADC's

Started by Martin Riddle July 18, 2009
I'm looking for a cheap 5v Rail buffered output 12bit DAC
And a 12bit ADC (8  channel).

Any recommendations?

Cheers
 


On Sat, 18 Jul 2009 15:30:31 -0400, "Martin Riddle"
<martin_rid@verizon.net> wrote:

>I'm looking for a cheap 5v Rail buffered output 12bit DAC >And a 12bit ADC (8 channel). > >Any recommendations? > >Cheers >
For the ADC, maybe an ADS7866 and an HC4051? John
Martin Riddle wrote:
> I'm looking for a cheap 5v Rail buffered output 12bit DAC > And a 12bit ADC (8 channel). > > Any recommendations? >
Define "cheap". Also, none of them truly goes to the rail if that's what you want. Many are 0V to 4.095V because that gives you a nice 1mV granularity. Others go by whatever external ref you provide. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
Martin Riddle wrote:

> I'm looking for a cheap 5v Rail buffered output 12bit DAC > And a 12bit ADC (8 channel). > > Any recommendations?
Depends on your requirements. There are huge price differences depending on speed. And there are different interfaces, like SPI or parallel and you might not like BGA style parts. A good source for selecting the right part is the parametric search at Digikey, even if you don't buy it there: ADC: http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=2556291 DAC: http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=2556292 Not cheap, but nice and fast is the LTC2624, which is on the Spartan3E evaluation kit, with which I've implemented my signal generator: http://www.frank-buss.de/SignalGenerator/ -- Frank Buss, fb@frank-buss.de http://www.frank-buss.de, http://www.it4-systems.de
Frank Buss wrote:
> Martin Riddle wrote: > >> I'm looking for a cheap 5v Rail buffered output 12bit DAC >> And a 12bit ADC (8 channel). >> >> Any recommendations? > > Depends on your requirements. There are huge price differences depending on > speed. And there are different interfaces, like SPI or parallel and you > might not like BGA style parts. > > A good source for selecting the right part is the parametric search at > Digikey, even if you don't buy it there: > > ADC: > http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=2556291 > > DAC: > http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=2556292 > > Not cheap, but nice and fast is the LTC2624, which is on the Spartan3E > evaluation kit, with which I've implemented my signal generator: > > http://www.frank-buss.de/SignalGenerator/ >
I like the AD5328 and the AD7928 but they aren't exactly cheap. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.

"John Larkin" <jjSNIPlarkin@highTHISlandtechnology.com> wrote in message 
news:t69465hsv9uugi3nknopg812toq8b9ofe3@4ax.com...
> On Sat, 18 Jul 2009 15:30:31 -0400, "Martin Riddle" > <martin_rid@verizon.net> wrote: > >>I'm looking for a cheap 5v Rail buffered output 12bit DAC >>And a 12bit ADC (8 channel). >> >>Any recommendations? >> >>Cheers >> > > For the ADC, maybe an ADS7866 and an HC4051? > > John > >
I should have mentioned SPI, But I think the AD7927 is the one, half the cost of the LT part we are using now. The are some Dacs that are priced right from analog too. If I had extra port pins then the Mux I would play around with, but thats not an option. Thanks
Martin Riddle wrote:
> "John Larkin" <jjSNIPlarkin@highTHISlandtechnology.com> wrote in message > news:t69465hsv9uugi3nknopg812toq8b9ofe3@4ax.com... >> On Sat, 18 Jul 2009 15:30:31 -0400, "Martin Riddle" >> <martin_rid@verizon.net> wrote: >> >>> I'm looking for a cheap 5v Rail buffered output 12bit DAC >>> And a 12bit ADC (8 channel). >>> >>> Any recommendations? >>> >>> Cheers >>> >> For the ADC, maybe an ADS7866 and an HC4051? >> >> John >> >> > I should have mentioned SPI, But I think the AD7927 is the one, half > the cost of the LT part we are using now.
That falls under "cheap"? Hmm, you guys leave too much money on the table :-)
> The are some Dacs that are priced right from analog too. > > If I had extra port pins then the Mux I would play around with, but > thats not an option. >
At that cost I'd consider muxing the SPI stream so you can hang a register onto the SPI that rotates through the ADC channels. Not an option for the DACs though. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
Joerg wrote:

> I like the AD5328 and the AD7928 but they aren't exactly cheap.
There are some cheap high quality audio DACs, but I don't know if they can go down to DC. -- Frank Buss, fb@frank-buss.de http://www.frank-buss.de, http://www.it4-systems.de
Frank Buss wrote:
> Joerg wrote: > >> I like the AD5328 and the AD7928 but they aren't exactly cheap. > > There are some cheap high quality audio DACs, but I don't know if they can > go down to DC. >
They used to, but at least the ADC part of audio codecs often has inherent highpass filtering in there which can't be turned off. Learned it the hard way when I wanted to hack a laptop into going down to below 1Hz. But it did go down to about 5Hz. Also you usually get only two channels. Example of a really cheap audio DAC, for 3.3V supply though: http://www.nxp.com/acrobat_download/datasheets/UDA1334TS_2.pdf They don't even spec the offset of the opamp that does the current to voltage conversion. It could very well be above the 12bit granularity because it doesn't matter to the audio guys. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
Joerg wrote:

> They don't even spec the offset of the opamp that does the current to > voltage conversion. It could very well be above the 12bit granularity > because it doesn't matter to the audio guys.
Sometimes it matters. If you have a sample rate change and you have to disable the output before changing the clock for the DAC to avoid any clicking noise, it could be a problem. I know a schematic with lots of transistors, op-amps and a relay, for which I've designed and implemented a software concept (including FPGA functions), which is really necessary to avoid any clicking noise for professional audio monitoring systems, where you can get deaf at signal levels of 0 dBu. I don't care, but looks like radio broadcasting customers do :-) -- Frank Buss, fb@frank-buss.de http://www.frank-buss.de, http://www.it4-systems.de