80C52-25 datasheets
CMOS 0 TO 44 MHZ SINGLE CHIP 8-BIT MICRONTROLLER
Related parts:Other documents
http://ozy.student.utwente.nl/projects/nms-6303/p80c32.pdf
D 80C32/80C52-25 : 0 to 25 MHz. D 80C32/80C52-30 : 0 to 30 MHz. D 80C32/80C52-36 : 0 to 36 MHz ... maximum high and low times specified on the Data Sheet ...