the input voltage range of a series voltage regulator. B. An analogous circuit for a current source. For good performance at high frequencies C1 should be small, or even eliminated altogether. where the i s are dotted, t s are crossed, and all is explained.
The solution is to add small ballasting resistors in the individual source leads, chosen roughly so that the voltage drop across them is at least comparable to the scatter in gatesource operating voltages. We’ve found that a few tenths of a volt drop is frequently adequate for MOSFETs of a given type, from a single manufacturing batch or from transistors selected for matched VGS;114 however, the datasheet specs would suggest (conservatively) larger drops – a volt or two at full operating current. Unless you are willing to worry about matched transistors, you should take the conservative approach to produce a robust design, with source-ballasting resistors sized to drop a volt or two at the currents where power dissipation becomes important.