Suggestions for a DAC/ADC

[Marks256]

Can anyone suggest a programmable A/D D/A chip? Serial communication to a microcontroller is preferred, but parallel is fine as well. 8 bits of resolution is plenty, no more than 16 bit resolution. Must have a minimum of 8 channels, but the more the better. 16+ channels is preferred.

If it exists, i would also like it so each channel is programmable independently to be A/D or D/A.


Hope i'm not getting my hopes up wishing a chip like this exists


Thanks all!

 

[blueroomelectronics]

They are almost always two different ICs. How fast is the sampling rate?

 

[Speakerguy]

Could you tell us a little more about the signals you'll be measuring (bandwidth, etc).

 

[Marks256]

Umm... I don't even know... Umm... Let's say a minimum of 4MHz? Just a guess. There really is no set value.


I did find an I2C ADC/DAC, but it was only a single channel.

 

[blueroomelectronics]

4Mhz is pretty fast for A/D. What's it for?

 

[Marks256]

I basically need to test a wide range of unknown inputs

4MHz is FAST for A/D?? :/ hmm... I suppose that would make sense.


Well how does an oscilloscope do it? They can do 100MHz, so how is that done? I don't need 100MHz, 10 would actually be more than enough. 4 would probably more than enough. But still, how does an o-scope do it?

 

[blueroomelectronics]

Flash A/D expensive per channel. what are you trying to build? A scope?

 

[Marks256]

what are you trying to build? A scope?

Well... technically yes... technically no. I'd rather not say what i'm building. but basically i want to build a logic analyzer, but i need analog inputs so i can tell if the input is tristate. So basically i want to make a logic analyzer that can tell if an input is in tristate as well.

I think i may just try to find a way to do this digitally, instead of having a 100k resistor goign to vcc and gnd and reading 2.5v if it is tristate.

 

[blueroomelectronics]

Well you don't need an A/D or D/A for a logic analyzer. Logic probes do tristate, analyzers normally do not (they are high speed latches).

 

[3v0]

I think i may just try to find a way to do this digitally, instead of having a 100k resistor goign to vcc and gnd and reading 2.5v if it is tristate.

eblc1388 told you how to do this in the other thread using a small cap ?

 

[Marks256]

Well you don't need an A/D or D/A for a logic analyzer. Logic probes do tristate, analyzers normally do not (they are high speed latches).

Well... see, i would also like the inputs to work as outputs, too. Digital and Analog outputs. So for digitial i could just output 0v and 5v, and analogue would just simply be analog. But it seems that is not possible at the moment, so i just may leave that functionality out.

told you how to do this in the other thread using a small cap ?

Yes, this is probably what i will use.