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Joined: 17 May 2005
Posts: 213
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| Digital to Analog Converter? |
 Posted: Wed Apr 19, 2006 1:17 am |
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Hi
I would like to make a digital (10 bit) to analog (0-10V) converter. Can someone please point me in the right direction?
Are there standard chips for this?
Thank you in advance.
a. |
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kender
Joined: 09 Aug 2004
Posts: 768
Location: Silicon Valley
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| Posted: Wed Apr 19, 2006 4:10 am |
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| Probably, the simplies solution to your problem is a voltage divider made of two 2k ressitors (assuming your Vcc=5V). What's generating the 10V analog output in your case? |
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Ttelmah
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| Posted: Wed Apr 19, 2006 5:01 am |
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Er. He is.....
I'd suggest looking at the MAX531. This can give -5v to +5v output, and is fairly easy to drive. Add an op-amp to give 0 to 10v. Alternatively run the ADC from a single 5v rail, and double the voltage in the op-amp stage.
This is generally cheaper, than any of the DAC's supporting this output range, directly...
Best Wishes |
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kender
Joined: 09 Aug 2004
Posts: 768
Location: Silicon Valley
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| Posted: Wed Apr 19, 2006 5:52 am |
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| kender wrote: | | Probably, the simplies solution to your problem is a voltage divider made of two 2k ressitors (assuming your Vcc=5V). What's generating the 10V analog output in your case? |
Kender, you have confused A/D with D/A... It's 3am - go to freakin' bed. |
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kender
Joined: 09 Aug 2004
Posts: 768
Location: Silicon Valley
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| Posted: Wed Apr 19, 2006 5:57 am |
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| Ttelmah wrote: | | I'd suggest looking at the MAX531. This can give -5v to +5v output, and is fairly easy to drive. Add an op-amp to give 0 to 10v. Alternatively run the ADC from a single 5v rail, and double the voltage in the op-amp stage. |
I'll add that if your system has only positive supply rails, you should use rail-to-rail opamp such as LMC6462, otherwise your output will not be able to go below 0.7V or so. |
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Ttelmah
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| Posted: Wed Apr 19, 2006 6:41 am |
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I know the feeling about going to bed at times...
On the 'op amp', you also need to be very careful in the +ve rail situation, that not only is the output 'rail to rail', but that the input common mode range includes the 0v rail. A lot of op-amps don't.
Best Wishes |
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SherpaDoug
Joined: 07 Sep 2003
Posts: 1640
Location: Cape Cod Mass USA
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| Posted: Wed Apr 19, 2006 7:06 am |
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Arrow,
Tell us what you power supplies are. That will have a big effect on the circuit to use. Ideally you should have +/- 15V or +/- 12V. If not, is there at least an RS232 drive chip we can steal a little negative voltage from? Working with no negative supply is hardest, but still possible.
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The search for better is endless. Instead simply find very good and get the job done. |
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