Based on the Linear Technology LTC2054, this -48 V circuit was found in a 2005 manual. The circuit is powered with 5 V and can be used as a shield.
This circuit is from Mullard documentation from 1969. Transistors support current equivalents. Output...
The integrated circuits of the SGS L79xx series are equivalent to those of the common 79xx series,...
This source, obtained in a 1973 publication, uses a low power transistor to regulate the output...