The MC145181 is a dual frequency synthesizer containing verylow supply voltage circuitry. The device supports two independent loops with a single input reference and operates down to 1.8 V. Phase noise reduction circuitry is incorporated into the device. The MC145181 operates up to 550 MHz on the main loop and up to 60 MHz on the secondary loop. The device has a 32/33 prescaler for the main loop. Lock detection circuitry for both loops is multiplexed to a single output.