This is the basic configuration of an operational amplifier sample & hold circuit. The FET and transistor are commonly used. The circuit is from an 80's documentation.
Equivalent transistors can be used on this 80's circuit. Any general purpose PNP transistor can work...
The configuration shown was found in an old American manual. The circuit can be made with modern...
Mouser Electronics counts in stock with the new TLV703 Low Dropout Voltage (LDO) Linear Regulators from Texas...