Sine Wave distortion measurements

Audioguru

Joined Dec 20, 2007
11,248
A lousy old LM324 or LM358 opamp has distortion of 3%.
A cheap TL07x audio opamp has distortion of only 0.003%.
A more expensive OPAx134 has distortion of only 0.00008%.
 

Audioguru

Joined Dec 20, 2007
11,248
Where is the distortion, crossover?
The LM358 and LM324 were the first low power opamps. They reduced the bias current in the output transistors to almost nothing (class-B) to reduce the power consumed which made up to 3% crossover distortion. If a resistor to ground or to the positive supply from the output is added then one transistor in the output operates in class-A with no crossover distortion but then the supply current is high.

An MC33171 single, MC33172 dual and MC33174 quad opamp operates with exactly the same low supply current and 3V minimum supply voltage but has no crossover distortion, has a max supply voltage much higher and has a full power bandwidth that is 7 times higher than the LM358 and LM324.
 
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