AVR-Chat

I looked and found several devices from Digi-Key that are 4.096 volt 
band-gap references.  These are much more stable and accurate than a 
zener. Some are 5-pin SMD devices and a couple are 8-pin devices.  But you 
basically put 5 to 15 volts on one pin and get 4.096 volts out of another 
pin. Even the two- and three-lead devices are more accurate than the 
zener.

That value is very useful for some circuits.  If you are going to use an 
AD8306 log amp as a received signal strength indicator (one of my 
projects), it produces 20 mV/dB.  So using 4.096 volts as the reference 
and a 10-bit ADC, every bit is equivalent to 0.2 dB.

Zack


On Wed, 3 Nov 2004, Dave Mucha wrote:

> 
> --- In AVR-Chat@yahoogroups.com, Dave VanHorn <dvanhorn@d...> wrote:
> >
> > >
> > >any suggestions on what to use for an external ref ?
> >
> > Any convenient band-gap chip will work. In my case, I used the
> 4.096V version.
> 
> 
> I hate to sound like a dummy, but sometimes the truth cannot be
> hidden.
> 
> Can you offer any type of link to how to use one ?
> 
> 
> I down loaded the TI data sheet for an LM-385, 3 pin TO-92 package
> unit and the unit is shown as a zener with the voltage after a
> resistor.
> 
> The idea of using 4.096 is interesting, but it would seem that 4.096
> would be the maximum voltage it could read ?
> 
> Dave
> 
> 
> 
> 
> 
> 
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