0 Replies Latest reply on Nov 7, 2009 9:11 AM by Bill_Case

# High and Low voltage numbers for my CPU and DRAM

I have the 102 page Intel Data Sheet in front of me.  I am trying to determine the High and Low voltage numbers for transistors on my system.

I am not trying to do anything mysterious or build a CPU in my garage.  I am just doing a small write up for myself that has an introductory paragraph for how DRAM memory works that says something like "My machine's CPU and Memory transistors typically use XXX volts when thrust High and XXX volts when driven Low."  I understand that things can get more complex, but I am only trying to establish a sense or feel of what is happening inside, not write a technical manual for engineers.

I am using the Intel 318732.pdf {Core 2 Duo Processor Data Sheet}.

lshw says I have a:
product: Intel(R) Core(TM)2 Duo CPU     E7400  @ 2.80GHz
vendor: Intel Corp.
bus info: cpu@0
version: Intel(R) Core(TM)2 Duo CPU
slot: Socket 775
size: 1600MHz
capacity: 4GHz
width: 64 bits
clock: 266MHz

and:

DIMM 800 MHz (1.2 ns)
Crucial DDR2 PC-2-6400 2GB Module

Gunning_Transceiver_Logic as the appropriate search criteria for what I wanted to know.  This site seems to cover it:

http://encyclopedia2.thefreedictionary.com/Gunning+Transceiver+Logic

"Gunning Transceiver Logic - (GTL) A standard for electrical signals in
CMOS circuits used to provide higher data transfer speeds with smaller
voltage swings The GTL signal swings between 0.4 volts and 1.2 volts
with a reference voltage of about 0.8 volts. Only a small deviation of
0.4 volts (or thereabouts) from the reference voltage is required to
switch between on and off states. Therefore, a GTL signal is said to be
a low voltage swing logic signal.

Gunning Transceiver Logic has several advantages. The resistive
termination of a GTL signal provides a clean signalling environment
Moreover, the low terminating voltage of 1.2 volts results in reduced
voltage drops across the resistive elements. GTL has low power
dissipation and can operate at high frequency and causes less
electromagnetic interference (EMI)."

Can I make the assumption that the voltages used on the FSB
would be the same as are used by transistors inside the CPU and DRAM?

I have been told that that kind of information is proprietory.  If so, can some one suggest a reasonable guess?  Or suggest another way of approaching the question?  e.g. electron count for the 45 nm technoglogy.