[Coco] 6809/6309 Power Analysis

[rjrtty at aol.com]

In a message dated 1/21/2010 9:15:04 P.M. Eastern Standard Time,  
gene.heskett at verizon.net writes:


>Boisy, I have NDI how the best measurement could be made, as the  dynamics 
for 
>the NMOS 6809 shouldn't show any really huge changes. 10%  maybe, and 
possibly 
>within the noise margin unless a large enough number  of samples is made 
for 
>each example.
 
 
Why not ground the 6809 using an opamp configured as a
current to voltage converter.   This will present no load  on
the circuit being sensed and a high performance op amp
with a low offset voltage will be fast enough at the speeds
of a 2 mhz 6809 or 6309.  You just need to choose an
appropriate feedback resistor and filter the supply of the
op amp to decouple it so as to reject noise from the
digital part of the circuit.  I would use the LM318.
It has a high slew rate and is a high precision
op amp.  It also has unity gain compensation
requiring no additional components.
 
Roy