Favorite quad op-amps for synth design?

Rene Schmitz uzs159 at uni-bonn.de
Thu Mar 23 23:53:07 CET 2000


At 06:49 23.03.00 -0800, Jim Patchell wrote:

>    The CA3130 was all Mosfet.  It had a CMOS output, which means it will do
>rail to rail, and came uncompensated.  As I recall, it was a little tricky to
>compensate, but not teribly so.  Also, because of the CMOS output, max supply
>voltage was about 15 volts.  I prefered to keep it down around 5 myself.
This
>opamp also made a good voltage comparator that could be used with 5 volt
logic
>(which is the way I used to primarily apply it).

The CA3130 has a fully compensated cousin: the CA3160. 
Main uses are single supply rail to rail apps. 

Here is my personal opamp selection philosophy:

TL081/2/4 "General purpose opamp" Uncritical CV or synth level (few Volts)
audio use.
Same applys to TL071/2/4. (I use whatever is cheaper!) Low input currents.

Use TL051/2 for increased speed. TL054 is not that fast.

LM411/12 for better offsets/drift. 

CA3140 really high Z, but in typical applications other factors might
delimit their usefulness. (e.g. S/H or integrators with a FET-switch that
has higher leakage than the opamps bias current. Often overlooked IMO, at
times a jFET opamp is the better choice.) Avoid audio usage. But output
includes the negative rail which is handy sometimes.

CA3130/3160 rail to rail swing, poor offset, poor output stage. Lower
supply voltage!

NE5534 lower noise, higher bias currents. Primarily for audio (100s mV).
Needs compensation.

Almost everything can be done using this few parts, using higher grade
parts only where it makes sense and can't be avoided.


Bye,
 René

(PS: The use of high grade parts doesn't make automagically a high grade
circuit!!!)


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