MC74HC4046AF

Clock Generators, PLLs, Frequency Synthesizers Overview

The MC74HC4046AF is a high-performance silicon-gate CMOS phase-locked loop (PLL) manufactured by onsemi. It integrates three distinct phase comparators, a linear voltage-controlled oscillator (VCO), and a unity gain operational amplifier (DEMOUT). The device operates within a supply voltage range of 3.0 V to 6.0 V and supports an operating temperature range from -55°C to +125°C. It features diode protection on all inputs and provides an output drive capability equivalent to 10 LSTTL loads. The component is housed in a 16-pin SOEIAJ package.

Clock Generators, PLLs, Frequency Synthesizers Feature Summary

• Integrates Phase Comparator 1 (XOR), Phase Comparator 2 (digital memory with tri-state output), and Phase Comparator 3 (edge-triggered RS flip-flop).
• Linear Voltage-Controlled Oscillator (VCO) with frequency determined by external R1, R2, and C1 components.
• Unity gain op-amp DEMOUT buffers the VCO input voltage for external access without loading the loop filter.
• Inhibit input disables the VCO and op-amps to minimize standby power consumption when set high.

Clock Generators, PLLs, Frequency Synthesizers Applications

• FM and FSK modulation and demodulation circuits.
• Frequency synthesis and multiplication systems.
• Tone decoding and data synchronization applications.
• Voltage-to-frequency conversion and motor speed control.

Clock Generators, PLLs, Frequency Synthesizers Procurement Notes

Verify the specific ordering suffix against the manufacturer's current documentation. Suffixes such as 'G' indicate Pb-Free packaging status, while 'EL' denotes tape and reel shipping quantities. Confirm that the SOEIAJ-16 package variant matches the required footprint and pinout specifications for the target design before procurement.

Clock Generators, PLLs, Frequency Synthesizers Selection Notes

Select this component when a single-chip PLL solution with multiple comparator options is required. Ensure the application voltage remains between 3.0 V and 6.0 V. Consider the specific phase comparator characteristics: PC1 for simple XOR logic, PC2 for zero-phase-lock detection with tri-state outputs, or PC3 for edge-sensitive operation. Verify external component values for R1, R2, and C1 to achieve the desired VCO center frequency and lock range.

Clock Generators, PLLs, Frequency Synthesizers Part Context

The MC74HC4046AF belongs to the 74HC4046A family of high-speed CMOS logic devices. It is functionally similar to the older MC14046 metal gate CMOS device but offers improved operating speeds comparable to LSTTL. The HC4046A series maintains pin compatibility with the 4000B series CD4046B, facilitating upgrades in existing designs requiring higher performance.

Clock Generators, PLLs, Frequency Synthesizers Replacement Considerations

Direct functional substitutes include the MC74HC4046AD (SOIC-16) and MC74HC4046ADT (TSSOP-16) from onsemi. Other manufacturers produce compatible parts such as the NXP 74HC4046AN and Texas Instruments CD74HC4046AE, though package dimensions and specific electrical tolerances should be verified for direct replacement.