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The low power CMOS IC [Integrated Circuit] was one of the key developments for the quartz watch.
The MOS IC used in the Riquartz 550, compare with the Seiko CMOS below, developed at roughly the same time, both first generation LSI.
From Cho family "In 1969, Manny Choy completed his assignment at Fairchild Semikor (Semiconductor Korea) in Seoul, and returned to Silicon Valley. He contacted AMI and got the agreement to build an AMI Assembly Plant in Korea. At the time, AMI had only a small Pilot Assembly Line at its Santa Clara facility and subcontracted most of its assembly to a Mexican company in Tijuana, Mexico. Since RICOH, an early electronic calculator manufacturer in Japan, was one of AMI's major customers, a Korean plant would make it very convenient to assemble, test and ship MOS-LSI directly from Korea to Ricoh in Japan. And this was how KMI began.
KMI experienced rough road of semiconductor business in second year, or the first year of real operation - 1971. As KMI demonstrated amazing yield improvement from the beginning of its regular production, AMI changed its initial policy from building only Ricoh's requirement at KMI to building all AMI's entire volume in KMI, except what they could produce in Santa Clara Pilot Line. This amounted to roughly 95% of total AMI volume, shutting their Tijuana operation down (Tijuana had a very serious problem coinci- dentally). KMI had to increase the capacity by more than 5 times in less than 3 months, as Tijuana volume had to be transferred to KMI before the contract with Tijuana company expired."
An early CMOS IC. Seiko claim this to be the first CMOS as used in the 38xx series, but it has 15 dividers meaning it is for 32,768KHz quartz, the 38xx were 16KHz (although later they did make some retrofit circuits using 32Khz quartz)
RCA were the first US manufacturer to offer CMOS chips.
81473 - Used in the 570, a very low profile ceramic package, with 3 or 4 figure date code
SC10018F, 300 transistors, as used in J-L Masterquartz.
Four digit date code, ie 7322 is 22nd week of 1973
Supplied IC for Riquartz 590 & 510, and Casiotron 04.
Cal 510 CMOS integrated circuit marked for example "7G2 841" for 2nd week of July 1977, made by Hitachi.
Example: 3B4 reads as 4th week in February of the year 1973
Earlier ICs could have two digit code, ie 1B for Feb 1971
Supplied IC for Casiotron 02 marked "MSM5920 4Y32" [for Nov 1974?]
The second character of the code is the last digit of the year of manufacture, the third character of the code is the 1-9 month production of January-September, the X - October, Y - November and Z - December. Example: 9951 reads as May of the year 1979
