The MC12181 is a monolithic bipolar synthesizer integrating a high
performance prescaler, programmable divider, phase/frequency detector,
charge pump, and reference oscillator/buffer functions. The device is
capable of synthesizing a signal which is 25 to 40 times the input
reference signal. The device has a 4–bit parallel interface to set the
proper total multiplication which can range from 25 to 40. When combined
with an external passive loop filter and VCO, the MC12181 serves as a
complete PLL subsystem.