This circuit consists of two stages that each shift 180 degrees the signal. The circuit was proposed by Siliconix in a 1966 publication. Equivalent FETs can be used.
We found this circuit in an old documentation from the 70s. The text is the original one of the...
The circuit shown in figure is suggested by Maxim in an application note. The operational...
We found this amplifier in a 1990 documentation. The transistors are common, having been made...