I was recently looking through a datasheet for a Sharp IR3M02 PWM
regulator and found the following information on date codes.

date code example 226A = 1st week of June, 1982

2 2 6 A
| | | |--- production week A,B,C,D,E (1st week)
| | |----- production month (1,2,3 ... 9,X,Y,Z)
| |------- denotes last digit of year (1982)
|--------- denotes the I.D. No.

I don't know if other Japanese manufacturers of that time used the
same coding, but I thought the information may be useful in any case.

- Franc Zabkar
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