CMOS auto-ranging PLL for low-voltage wideband systems

Describes a low-voltage PLL circuit using auto-ranging technique designed for implementation in the MOSIS 1.5 μm CMOS technology. The PLL circuit is equipped with a self-sensed/adjusted capacity in response to a large, fast acquired-frequency switch, and also has good immunity to temperature, processing, and supply voltage variations. The experimental result confirms the functionality of the auto-ranging mechanism of the fabricated PLL IC over a frequency range of 55-400 MHz with a 2.5-volt power supply.