CD4046 Micro-power Phase-locked Loop

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CD4046 belongs to the CD4000 IC series. The CD4046 micropower phase-locked loop (PLL) consists of low power, linear, voltage-controlled oscillator (VCO), a source follower, a Zener diode, and two-phase comparators. The two-phase comparators have a common signal input and a common comparator input. The signal input can be directly coupled for a large voltage signal, or capacitively coupled to the self-biasing amplifier at the signal input for a small voltage signal. The IC offers a wide variety of features such as high noise immunity and low-frequency drift with a stabilized linear output.

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What is a Phase Locked Loop (PLL)?

A phase locked loop is an electronic configuration that consists of a phase detector, voltage controlled oscillator and a loop filter as well as a reference signal source. Within the phase locked loop, the incoming reference hits the phase detector along with a signal from the PLL voltage controlled oscillator. A signal proportional to the phase difference between the two is generated and this is passed through a loop filter to remove unwanted signals. The resulting error signal is applied to the input of the VCO with the effect that the phase between the reference and the VCO signals is reduced. Eventually, a point is reached where a steadily fixed phase difference exists. At this point, the phase lock loop is said to be in the lock and the frequency of the reference and VCO are exactly the same.

CD4046 Key Features

Wide supply voltage range: 3.0V to 18V
Low dynamic power consumption: 70 µW (typ.) at fo = 10 kHz, VDD = 5V
VCO frequency: 1.3 MHz (typ.) at VDD = 10V
Low frequency drift: 0.06%/°C at VDD = 10V with temperature
High VCO linearity: 1% (typ.)

CD4046 Pinout

Pin No	Pin Name	Description
1	Phase Pulse	Phase pulse applied to the IC
2	Phase- Comp I Out	output of Phase Comparator I
3	Comparator IN	Input at the Comparator
4	VCO OUT	Output Signal at VCO
5	INHIBIT	electronically turn on or off the output voltage
6	C1A	Capacitor 1 connected to VCO
7	C1B	Capacitor 2 connected to VCO
8	VSS	source supply
9	VCO IN	Input Signal at VCO
10	D- OUT	Extracting the original signal
11	R1	Resistor 1 connected between VCO and Supply Voltage
12	R2	Resistor 2 connected between VCO and Supply Voltage
13	Phase- Comp II OUT	Generated oscillated output at Phase II Comparator
14	Signal IN	Input Signal applied to the Phase Comparator I
15	Zener	Zener diode for voltage regulation
16	VDD	Drain supply