Beau Scwabe said...
I believe it refers to the technology or process used...
A CMOS transistor has a Source and Drain connection thus Vss corresponds to the Source and Vdd corresponds to the Drain.
A Bipolar transistor has a Collector and an Emitter thus Vcc corresponds to the Collector and Vee corresponds to the Emitter.
I am not exactly sure why there is a double stamp representation unless it represents a hierarchical nomenclature.
microcontrolleruser wrote: »
VDD is 5 volts regulated.
VCC is whatever is coming in on your power supply.Unregulated.
VSS is ground or 0 volts.