PLL frequency synthesizer with multi-programmable divider

The lock-up time of a PLL frequency synthesizer depends on each loop gain. In this paper, we pay attention to the gain of a programmable divider which is one of the important elements of PLL, and propose a new method for improving the gain of programmable divider. In order to achieve the increase in gain of the programmable divider, we propose a new PLL frequency synthesizer with multi-programmable divider by which the gain is increased even when the same reference frequency and the same division ratio as usual are used. It will be shown by the theoretical considerations and experimental results that a higher speed lock-up time can be achieved.