11C90 - National

11C90 650 MHz Prescalers

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 control.

Features

so allows power consumption to be reduced by leaving the separate VEE pin open if the TTL output is not used To facilitate capacitive coupling of the clock signal a 400X resistor (VREF) is connected internally to the VBB reference Connecting this resistor to the Clock Pulse input (CP) automatically centers the input about the switching threshold Maximum frequency operation is achieved with a 50% duty cycle Each of the Mode Control inputs is connected to an internal 2 kX resistor with the other end uncommitted (RM1 and RM2) An M input can be driven from a TTL circuit operating from the same VCC.