آِ سی V4046 یا 4046 یک حلقه  قفل فاز ( Phase-Locked Loop ) از نوع CMOS با راندمان بالا می باشد.

The device inputs are compatible with standard CMOS outputs;
with pullup resistors, they are compatible with LS/ALSTTL outputs.
The SL74HC4046 phase-locked loop contains three phase comparators, a voltage-controlled oscillator (VCO) and unity gain opamp DEM.
The comparators have two common signal inputs, COMPINOUT, and
SIGIN. Input SIGIN and COMP can be used directly coupled to large voltage signals, or indirectly coupled (with a series capacitor to small voltage signals). The self-bias circuit adjusts small voltage signals in the linear region of the amplifier. Phase comparator 1 (an exclusive OR gate) provides a digital error signal PC1in  and maintains 90 degrees phase shift at the center frequency between SIG and COMP signals (both at 50% duty cycle). Phase comparator 2 (with leading-edge sensing logic) provides digital error signals PC2in and PCPout and maintains a 0 degree phase shift between SIG and COMP signals (duty cycle is immaterial). The linear VCO produces an output signal VCOin whose frequency is determined by the voltage of input VCOin , OUT signal and the capacitor and resistors connected to pins C1A, C1B, R1 and R2. The unity gain op-amp output DEM
 IN with an external resistor is used where the VCOin signal is needed but no loading can be tolerated. The inhibit input, when high, disables the VCO and all on-amps to minimize standby power consumption. Applications include FM and FSK modulation and demodulation, frequency synthesis and multiplication, frequency discrimination, tone decoding, data synchronization and conditioning, voltage-to-frequency conversion and motor speed control.

• Low Power Consumption Characteristic of CMOS Device
• Operating Speeds Similary to LS/ALSTTL
• Wide Operating Voltage Range: 3.0 to 6.0 V
• Low Input Current: 1.0 mA Maximum (except SIGin and COMP)
• Low Quiescent Current: 80 mA Maximum (VCO disabled)
• High Noise Immunity Characteristic of CMOS Devices
• Diode Protection on all Inputs