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Conference ricks::dechips

Title:Hudson VLSI
Notice:For Digital Chip Data - CHIPBZ::PRODUCTION$:[DS_INFO...]
Moderator:RICKS::PHIPPS
Created:Wed Feb 12 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:701
Total number of notes:4658

653.0. "Klamath varible voltage technology" by STAR::JACOBI (Paul A. Jacobi - OpenVMS Development) Fri Feb 21 1997 17:15

    I understand that the new Intel Klamath processors will run at various
    voltages between 2V and 3V.  I have read that the exact voltage will
    be encoded on the chip during wafer probe and is likely to vary from
    different wafer lots.  The power supply for Klamath system must be
    smart enough read the voltage requirement of the chip and supply the
    proper voltage.

    This sounds like a great way to increase yield and speed bins.  I also
    seem to remember that "Hot Pink Flamingo" Alpha systems were able to run
    a little faster by increasing the voltage.

    Is Digital Semiconductor planning to adopt this technology on future
    Alpha chips?


    							-Paul

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653.1YIELD::HARRISFri Feb 21 1997 18:517
    We do this all the time. Oversimplifying it, adjust voltage up to
    increase speed (and power consumption), down to decrease power
    consumption (and speed). EV56 was designed to run around 2.2v, but we
    are running it around 2.5v to get the speed we need.
    
    -Bruce

653.2WRKSYS::INGRAHAMAndyFri Feb 21 1997 19:4315
... except that with Alphas, thus far, the voltage setting is only a
function of the system it's put into.


With the EV56, there had been plans to specify two target voltage
ranges for the "core" supply, depending on whether it was a Pass 1 or
Pass 2 EV56, the first using "High Vdd" transistors and the other
"Enhanced" transistors with more speed but a little less voltage
capability.  A pin on the EV56 was dedicated for telling the system
which voltage setting to use.

Then the process engineers determined that the "Enhanced" transistors
could withstand the same slightly higher core voltage as the "High
Vdd" transistors, so the need for adjusting the voltage based on this
pin was dropped.
653.3Maxim, LT, etc are on this bandwagon..TEKVAX::KOPECConsider a spherical chicken; ..Fri Feb 21 1997 21:378
    I've been seeing a lot of stuff in the trade rags and in my mail from
    various chip vendors about this.. clearly, there is a lot of activity
    in the power semi market to support this.. 
    
    Should DS want to do this, we should try to leverage these commodity
    power supply parts.. at least by picking some compatible encoding..
    
    ...tom
653.4CAMPY::ADEYIs there a 'Life for Dummies'?Mon Feb 24 1997 15:025
    Isn't this variable voltage mechanism really part of the patented
    interface Intel is employing for the Klamath to put the clone makers
    (AMD, IBM/Cyrix) out of business?
    
    Ken....