[sdiy] Inverting Amplifier as a Buffer Output.

[Neil Johnson]

Hi,

On 23 Jun 2010, at 23:00, Antti Huovilainen wrote:

> On Wed, 23 Jun 2010, Oscar Salas wrote:
>
>> In which way could the case B) drive the opamp out of compliance  
>> if there is low input impedance. What I should expect?
>
> As far as stability goes, case B is pretty much same as no output  
> resistor at all. Opamps really hate uncompensated capacitance at  
> the negative input and a normal coaxial audio cable will have  
> perhaps 100 pF / meter parasitic capacitance.

For case B) also put a small (typically 10pF) capacitor from the  
output to the -ve input.  Keeps gain controlled at high frequencies.

Neil
--
http://www.njohnson.co.uk