Monday, March 1, 1999
Today, at the JEDEC Memory committee meeting
in Las Vegas, CST, Inc. announced that it is taking up the task of manufacturing and
distributing the "PC100/PC133 DIMM clock reference board" designed by IBM's Micro Electronic Division.
This ‘Clock
Reference Board’ can serve as a test vehicle for Module producers (to
‘tune’ the module assembly during validation), and as a qualification vehicle
for system producers. The board consists of a clock generator and a seven-output buffer.
Four of the clock signals go to the DIMM module socket while other lines go to the
on-board industry defined reference net circuit. Oscilloscope waveform measurement is made
at the DRAM and compared against the measurement at the reference net for time delay and
skew.
 CST, Inc. will be building all the boards in one batch to
ensure consistency. A ‘gold’ board will be maintained to support future builds.
Background:
Current JEDEC and industry de-facto standards do not provide a method for ensuring
memory module (SDRAM/register) clock timing accuracy. Previous JEDEC and Intel
specifications define the clock structure in good detail, but provide no measurement
method or delay value at the DIMM-level. ‘PC100-compliant’ DIMMs, from major
suppliers, vary by greater than 1ns (10% of cycletime!) in clock arrival at SDRAM.
Computer system manufacturers have selected various clock delay measurement solutions and
specs, driving suppliers to have inconsistent clock delays. With increased SDR clock
speeds, as well as with DDR DIMMs emerging, improved clock definitions and measurement
techniques are needed.
CST, Inc
Founded in 1983, CST develops, markets, and supports computer memory tester
software and hardware. CST pioneered the first low cost SIMM tester for computers in 1985.
Since then, CST testers have become the standard for the computer industry, holding more
than 70% of the market in memory testers for computer manufacturers and third party memory
module manufacturers. With its product lines of SIMM/ DIMM memory tester and handler, CST
is equipped to handle all aspects of memory testing. CST has a comprehensive line of
testers ranging from the low volume service tester to the high-volume production tester.
Contact: CST, Inc. 2336 Lu Field Road, Dallas, Texas 75229,
USA. (972)241-2662, e-mail cst@simmtester.com, URL: www.simmtester.com.
By: CST Staff
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