4046 IC Phase-locked loop

CD4046 is a Micropower Phase-Locked Loop (PLL) that comes with a phase detector for comparing the phase of the output signal with the input signal and adjusting them in order to make the matching signals from both ends.

• It comes with a common comparator input and a common signal input amplifier between a low-power linear voltage-controlled oscillator (VCO) and two different phase comparators.

The input signal can be operated in two ways: capacitively layered with a self-biasing amplifier for creating a small voltage signal or directly coupled for a large voltage signal.

• The VCO (Voltage Controlled Oscillator) is an integral part of the IC that mainly generates oscillated frequency based on the applied input. The generated frequency is then used for phase modulation.

The chip features two phase comparators i.e. Phase Comparator I and Phase Comparator II. They are also known as Phase Detectors.

Phase comparator I is nothing but an exclusive OR gate that produces a digital, maintaining 90° phase shifts at the VCO.

• It is important to note that both signal input and comparator input are set at 50% duty cycle where Phase Comparator I can lock the input frequencies that match with the magnitude of the VCO center frequency.

Similarly, Phase comparator II is known as an edge-controlled digital memory network and maintains a 0° phase shift between signal input and comparator input, providing a lock-in and digital error signal.