IC power-supply pin

Voltage designations, which are found in almost all schematics and data sheets, and which one (! Eg with Eagle or TARGET 3001 ) can create with EDA programs, for example, are the following:

  • Positive voltage: VDD, VCC
  • Negative voltage: VSS, VEE

They come from the Anglo- Saxon world, such as the V for voltage, instead of the usual in German and corresponding to the SI system U (from the Latin urgere ) for the electric power it shows. Since many large semiconductor and device manufacturers originate from the U.S. or traditional, these names have become widespread. The index letters ( often Lowered or at least presented in a smaller font size) D, S, C, and E were incurred in the name of the terminals ( ports ) of a transistor. For example, the drain and source (MOSFET ) and collector, emitter ( bipolar ). Duplicate indexes such as CC or DD are usually available for supply voltages to ground.

Specific designations

Double indexing, in most cases, a plural form, that is a generalization. Thus, it is not the voltage at a certain pin of the individual part. So referred to as VCC originally the collector voltages of several components. Absolute differentiation of voltage designations, for example, between VCC and VDD, since the alternating / simultaneous use of TTL logic and CMOS logic has been blurred.

Here are some of the most popular names at a glance:

  • VB - voltage at the base
  • VBB - compound of bulks ( troughs ) of the MOSFETs, usually 5V, not the voltage at the base pins of several transistors!
  • VBAT - Battery voltage
  • VBE - voltage between base and emitter of a bipolar transistor
  • VC - is the voltage at the collector ( collector) of a bipolar transistor
  • VCC - plural formation: voltage at the collectors, positive for bipolar IC supply voltage
  • VCE - voltage between collector and emitter of a bipolar transistor
  • VCEsat - voltage between C and E in the saturation state of the transistor
  • VCM - mid-voltage integrated circuits used in asymmetric power
  • Vcore - the power supply for the "important" chips, such as CPU or GPU
  • VD - voltage at the drain of a FET
  • VDS - voltage between drain and source in FET's
  • VDD - positive supply voltage of MOS circuits ( the position at the number of " drain " of the NMOS logic hang )
  • VDDQ - The power supply for the output buffer of a memory chip
  • VE - voltage at the emitter
  • VEE - voltage at the emitters, negative supply voltage eg ECL ICs
  • VG - voltage at the gate
  • VGS - voltage between gate and source in FET's
  • VIN - Input voltage
  • VMEM - The power supply for a memory chip / memory module, sometimes also: VDDR, VDIMM or similar
  • VOUT - output voltage
  • VPP - voltage difference between the positive and negative peak voltage (peak to peak), but also programming voltage at (E ) EPROMs and microcontrollers
  • VREF - the reference voltage
  • VRMS - root mean square, RMS value of a voltage
  • VS - voltage at the source
  • VSS - negative power supply voltage of the MOS circuits, often identical to GND (see below)
  • VTT - connection of the terminating resistors ( terminators)

General terms

Moreover, there are even more general terms for positive and negative supply voltages, such as:

  • V - positive supply voltage ( say not more than the voltage level from! )
  • V - positive supply voltage ( say not more than the voltage level from! )
  • V - negative supply voltage
  • V - - negative supply voltage
  • GND - 0V, 0 - potential, mass, short for. " Ground". Against this potential is the voltage or " potential difference " measured. The voltage potential positive voltages is higher than GND, negative voltages have a voltage potential that lies below GND. Colloquially GND is often mistakenly referred to as a negative supply voltage. A scale ( positive or negative ), current flows on the GND line back to the voltage source.
  • CGND - " Chassis Ground" - which is usually connected to the housing
  • SGND - "Signal Ground" - often used for negative voltage level in analog circuit components, eg audio
  • DGND - "Digital Ground" - in conjunction with digital components with analog input
  • AGND - " analog ground " - analog signals into digital modules often have a separate Ground

The problem with these names is: It is only ever just to name no means mandatory standards or standards. For the award of such names in the schematic design should therefore be always great due diligence, and only then introduce new or additional name when the supply voltage has actually physically decoupled from other operations in the circuit voltages ( for example, via a choke coil ), and if they at several Bauteilepins is employed.

  • Voltage
740801
de