The MC145220 is a lowvoltage, singlechip frequency synthesizer with serial interface capable of direct usage up to 1.1 GHz. The device simultaneously supports two loops. The two onchip dualmodulus prescalers may be independently programmed to divide by either 32/33 or 64/65. The device consists of two dualmodulus prescalers, two 6stage A counters, two 12stage N counters, two fully programmable 13stage R (reference) counters, and two lock detectors. Four phase/frequency detectors are included: two with current source/sink outputs and two with doubleended outputs.