Vdd

Hi

i would like to know what is the definition of VDD (Voltage Drain Drain) and what is the main function of this?
i've tried searching the web but I didn't find any answer to my question.

thank you in advance

tintincute said:

Hi

i would like to know what is the definition of VDD (Voltage Drain Drain) and what is the main function of this?
i've tried searching the web but I didn't find any answer to my question.

thank you in advance

Click to expand...

Vdd refers to the positive operating voltage of a field effect semiconductor device.

Is this what you mean.?

EDIT: https://en.wikipedia.org/wiki/Vcc

https://sandeep-vaniya.blogspot.com/2008/04/what-is-vccvdd-veevss.html

This is the only place in a quick search that gave an explanation for the double subscript Vdd, as opposed to Vd.

Ken

This is an excerpt from a site i found years ago, but I can't remember where.. Hope it helps...
Regards
Jim


Positive voltages:
Vcc- Positive supply voltage of a Bipolar Junction Transistor.
Vdd- Positive supply voltage of A Field Effect Transistor

Negative voltages/ground:
Vee- Negative supply voltage of a Bipolar Junction Transistor.
Vss- Negative supply voltage of A Field Effect Transistor.

The letters c,d,e and s originated from the name of the legs of the transistors Collector, Drain, Emitter and Source.

The absolute distinctions between these common supply terms has since been blurred by the interchangeable application of TTL and CMOS logic families. Most CMOS (74HC / AC, etc.) IC data sheets now use Vcc and Gnd to designate the positive and negative supply pins.

The doubled suffix indicates that the voltage is "common", i.e. it is the supply voltage to one or more collectors (in the case of cc) and not just the voltage at a specific collector. Similarily, Vee is a common voltage for all emitters etc.

It looks like the Site Ken gave is where I originally got it from... Sorry !

hey thanks a lot. i guess this is what i'm looking for.

"The letters c,d,e and s originated from the name of the legs of the transistors Collector, Drain, Emitter and Source."

this is now familiar to me. i almost forgot all the theories i've learned 7 years ago. thanks to this site. will surely come back(-;

It dates back to the dates of NMOS - the +V goes to the drains so it was called Vdd.

These days CMOS is used and both the positive and 0V lines are connected to the drains so it doesn't make any sense but the term stuck.