The CD4046BC micropower phase-locked loop (PLL) consists of a 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.Phase comparator I, an exclusive OR gate, provides a digital error signal (phase comp. I Out) and maintains 90° phase shifts at the VCO center frequency. Between signal input and comparator input (both at 50% duty cycle), it may lock onto the signal input frequencies that are close to harmonics of the VCO center frequency. Phase comparator II is an edge-controlled digital memory network. It provides a digital error signal (phase comp. II Out) and lock-in signal (phase pulses) to indicate a locked condition and maintains a 0° phase shift between signal input and comparator input. The linear voltage-controlled oscillator (VCO) produces an output signal (VCO Out) whose frequency is determined by the voltage at the VCOIN input, and the capacitor and resistors connected to pin C1A, C1B, R1 and R2. The source follower output of the VCOIN (demodulator Out) is used with an external resistor of 10 kW or more. The INHIBIT input, when high, disables the VCO and source follower to minimize standby power consumtion. The zener diode is provided for power supply regulation, if necessary.
Wide supply voltage range: 3.0V to 18V
Low dynamic power consumption: 70 mW (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