This part is a kind of semiconductor called 11C90.

Function of this product has 650 MHz Prescalers.

Manufacturers : National

Image and pinout :

Some of the text within the PDF file :

11C90 11C91 650 MHz Prescalers Not Intended For New Designs August 1992 11C90 11C91 650 MHz Prescalers General Description The 11C90 and 11C91 are high-speed prescalers designed specifically for communication and instrumentation applications All discussions and examples in this data sheet are applicable to the 11C91 as well as the 11C90 The 11C90 will divide by 10 or 11 and the 11C91 by 5 or 6 both over a frequency range from DC to typically 650 MHz The division ratio is controlled by the Mode Control The divide-by-10 or -11 capability allows the use of pulse swallowing techniques to control high-speed counting modulos by lower-speed circuits The 11C90 may be used with either ECL or TTL power supplies In addition to the ECL outputs Q and Q the 11C90 contains an ECL-to-TTL converter and a [ ... ]

11C90 PDF Datasheet Download