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Am 19.05.2010 16:16, schrieb Invisible:
> While we're here, does anybody comprehend what VCC, VSS, VDD and related
> symbols mean?
According to JEDEC,
VBB = substrate power voltage (bias voltage), a voltage < VSS/GND.
VCC = logic power voltage, serving as a reference for high signal levels
(often sharing a common rail with VDD, in which case they may be used
interchangeably).
VCCQ = output stage logic power voltage, separate (positive) power rail
to drive output loads.
VDD = drain power voltage. separate (positive) power rail to drive the
chip's internals.
VDDQ = output stage drain power voltage. Effectively the same as VCCQ.
VEE = emitter power voltage. Only used for ECL devices.
VHH = special function enable voltage. An extra-high voltage to enable
certain special functions of a device.
VPP = programming voltage. An extra-high voltage to supply the power for
the programming function of a device (e.g. EPROM)
VREF = reference power supply, serving as a special reference voltage,
e.g. for ADC inputs.
VSS = GND = ground reference / source power voltage, serving as both
(negative) power rail and low signal level reference.
VSSQ = GNDQ = output stage source power voltage / ground reference,
serving as both a (negative) power rail and low signal level reference
specifically for output signals (should always be at the same level as
VSS=GND).
(This is just a subset of all the symbols used; for instance,
digital/analog devices such as programmable amplifiers or ADCs/DACs
often use separate voltage rails for the analog signals.)
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