The invention of the bipolar transistor in 1947 by William Shockley, John Bardeen, and Walter Brattain marked a pivotal moment in electronics. By the 1960s, logic circuits predominantly relied on these bipolar transistors, particularly favoring the faster NPN variants for their logic implementations. This era associated the positive supply voltage with VCC (Voltage Collector Collector), reflecting its connection to the collector terminal of NPN bipolar transistors. At times, the negative supply voltage was termed VEE (Voltage Emitter Emitter), linked to the emitter of these transistors.
William Shockley
TThe first practical point-contact transistor at 1947
In contrast, MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) emerged from the 1959 invention by Mohamed Atalla and Dawon Kahng. With MOSFET-based logic circuits, a new naming convention arose. VDD (Voltage Drain Drain) signified the positive supply voltage, linked to the drain terminal of the MOSFET, while VSS (Voltage Source Source) represented the negative supply voltage, tied to the source terminal.
Mohamed Atalla and Dawon Kahng
Over time, MOSFET technology gained prominence due to its advantages over bipolar transistors, such as High Switching Speed, Low Power Consumption, and High Efficiency. Notably, the first microprocessor, the 4004, embraced MOSFET technology, utilizing around 2,300 transistors on a single chip.
This shift in transistor technology led to the adoption of terms like VDD and VSS as standard labels in the semiconductor industry. Despite this, owing to historical familiarity, VCC and VEE continued to hold significance in certain contexts. Today, VCC and VDD are often used interchangeably to represent the positive supply voltage, while VEE and VSS similarly interchangeably denote the negative supply voltage in electronic circuits, showcasing the evolution of terminology shaped by historical implementations and technological advancements.
| VCC | Positive | NPN - Collector (集电极) |
| VEE | Negative | NPN - Emitter (射极) |
| VDD | Postive | N-Mosfet - Drain ( 漏极) |
| DVDD | Postive | D - Digital Refer to Digital Circuit |
| AVDD | Postive |
A - Analog |
| VSS | Negative | N-Mosfet - Source (源极) |
| VBAT | Postive | BAT - Battery |
| Ground | 0V | Voltage Reference |
You can also use a mnemonic device to remember the correspondence between certain terms in electronics and their representations on a music CD. Here's a breakdown:
Write CD (Compact Disc) at the front side of the disc:
C represents VCC (Voltage Collector Collector).
D represents VDD (Voltage Drain Drain).
The front side of the CD is associated with the positive aspects.
Write ES (Extra Storage) at the bottom side of the disc:
E represents VEE (Voltage Emitter Emitter).
S represents VSS (Voltage Source Source).
The bottom side of the CD is related to the negative aspects.
This mnemonic helps to associate certain electronic voltage terms (VCC, VDD, VEE, VSS) with the sides of a music CD, making it easier to recall and remember.
