The way I deal with this is to name my supplies with the actual voltages, e.g., +5V, +3.3V, etc. If there are analog and digital supplies at the same voltage, I use +3.3V_A, +3.3V_D. There’s absolutely no confusion with this naming convention.?
Tony - AC9QY
Hi Kees
The component library names for things are sometimes different from the schematic net names. This is a case of that. The 74CBT3253 calls it's supply pins Vdd. They are on the +5V rail in QMX which happens to be called Vcc.
It IS all confusing...
The way I think of it - which I believe (perhaps incorrectly) to be the most common usage is:
Vcc is for bipolar transistors, C = Collector; going back half a century to 74-series TTL (transistor transistor logic) they ran off +5V so in my schematics Vcc is +5V.
Vdd is for CMOS/MOSFETs where D = Drain. And commonly or at least, often, ok, sometimes, this means a +3.3V supply. So in my schematics Vdd is +3.3V.
73 Hans G0UPL
Looking at the schematics, I thought VDD was 3.3V and VCC was 5V but they seem to be interconnected like on the 74CBT3253 schematic power pins.
73 Kees K5BCQ
