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cheap programmable divider (Read 2309 times)

vivkr Community Fellow Offline Posts: 780	cheap programmable divider Mar 28^th, 2008, 8:15am Hi, I was wondering if there was a good way to make a cheap programmable resistive divider, say 6-8 bit? Thanks Vivek
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HdrChopper

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Re: cheap programmable divider
Reply #1 - Mar 30^th, 2008, 3:01pm

Hi Vivek,

I think the trade off between achieving such resolution and making a cheap resistor divider is (and I'm sure you know it) the R-2R ladder structure. You would need 2^N taps (N= number of bits) and your divider would only have unit cells of size R. Making a straightforward resistor divider by using equally sized resistor for each tap would require much more parallel/series combination for such resolution than the ones you need for the R-2R structure.

Hope this helps
Tosei.

Keep it simple

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vivkr Community Fellow Offline Posts: 780	Re: cheap programmable divider Reply #2 - Mar 31^st, 2008, 11:08pm Hi Tosei, Thanks for your reply. Indeed, the basic tradeoff is clear. I need to see if I can use an R-2R ladder. I think this will be a problem for me because I need to keep the overall ladder resistance more or less constant (not too much variation). Perhaps I can try some variation on this one. Vivek
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