[sdiy] R2R ladder with feedback loop?

[Tavys Ashcroft]

Higher value resistors will draw less current.  Was there a reason you
wanted to use 100 ohm resistors?

You can also get matched resistor networks specifically designed for
R2R networks.  Vishay and Semiconwell make good R2R ladder networks.
They're cheap, too.  That way you don't have to worry about
hand-matching 1% resistors for accuracy.  Still not as good as a real
DAC, but pretty good for a cheap solution.

-Tavys

On 8/19/06, Karl Ekdahl <elektrodwarf at yahoo.se> wrote:
> Hi list,
>
> I want to throw together a simple R2R ladder using 1%
> 100 ohm resistors, the problem is that a standard
> configuration would draw way too much current. I was
> thinking that there has to be some neat little op-amp
> feedback trick that can overcome this problem but
> can't think of it myself.
>
> Any ideas?
>
> Thanks
>
> Karl
>