Other useful info
Last modified 2007-05-02
MC145106, MM55106, MM55116 and MM55126
PLL frequency synthesizer
The MC145106 has circuitry for a 10.24 MHz oscillator or may operate with an external signal. The circuit provides a 5.12 MHz output signal, which can be used for frequency tripling. A 512 programmable divider divides the input signal frequency for channel selection. The inputs to the programmable divider are standard groundtosupply binary signals. Pull-down resistors normally set these programmable inputs to ground, enabling them to be controlled from a mechanical switch or electronic circuitry.
The phase detector may control a VCO and yields a high level signal when input frequency is low, and a low level signal when input frequency is high. An out-of-lock signal is provided from the on-chip lock detector with a "0" level for the out-of-lock condition.
Down-converting of the frequency to the divider
The XTAL frequency is f XTAL = f OUT - f IN