MC74HC4046BDTR2G

Clock Generators, PLLs, Frequency Synthesizers Overview

The MC74HC4046BDTR2G is a high-performance silicon-gate CMOS phase-locked loop (PLL) manufactured by onsemi. It integrates three phase comparators, a voltage-controlled oscillator (VCO), and a unity gain operational amplifier. The device operates with a VCC supply range of 3.0 V to 6.0 V for the VCO section and 2.0 V to 6.0 V for non-VCO sections. It features low quiescent current (80 µA max with VCO disabled) and input diode protection. Packaged in a TSSOP-16 surface-mount format, it supports applications requiring frequency synthesis, modulation, and data synchronization.

Clock Generators, PLLs, Frequency Synthesizers Feature Summary

• Integrates Phase Comparator 1 (XOR), Phase Comparator 2 (edge-sensitive), and Phase Comparator 3 (RS flip-flop based).
• Voltage-Controlled Oscillator (VCO) operating range supported by external R1, R2, and C1 components.
• Unity gain op-amp output (DEM OUT) buffers the VCO input voltage without loading the loop filter.
• Inhibit input disables the VCO and op-amps to minimize standby power consumption.

Clock Generators, PLLs, Frequency Synthesizers Applications

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

Clock Generators, PLLs, Frequency Synthesizers Procurement Notes

Verify the ordering suffix 'R2G' corresponds to the TSSOP-16 package and tape-and-reel shipping configuration. Confirm RoHS compliance and lead-free status as specified in the manufacturer's ordering information. Ensure the procurement source provides valid traceability documentation for the specific manufacturing lot.

Clock Generators, PLLs, Frequency Synthesizers Selection Notes

Select this component when a CMOS-compatible PLL with multiple phase detector options is required. The HC4046B inputs are compatible with standard CMOS outputs and LSTTL outputs with pullup resistors. Consider the specific phase comparator characteristics: PC1 for 90-degree phase shift, PC2 for 0-degree shift with tri-state output, or PC3 for edge-triggered 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

This part belongs to the MC74HC4046B series of phase-locked loops. It is functionally similar to the older MC14046 metal gate CMOS device but utilizes high-performance silicon-gate technology. The 'D' suffix indicates the SOIC/TSSOP package family, while 'T' specifies the TSSOP-16 form factor. The 'R2G' suffix denotes the reel packaging and Pb-free/RoHS compliant construction.

Clock Generators, PLLs, Frequency Synthesizers Replacement Considerations

Public confirmed substitute part numbers include MC74HC4046AFEL and MC74HC4046AFELG from ON Semiconductor. Other manufacturers such as Nexperia offer equivalent devices like the 74HC4046ADB. Verify pin compatibility and electrical specifications before substitution.

Clock Generators, PLLs, Frequency Synthesizers FAQ

What is the function of the DEM OUT pin?

The DEM OUT pin provides the output of a unity gain operational amplifier that buffers the VCOIN signal. This allows the VCO input voltage to be accessed externally without degrading loop performance due to loading effects.

How does Phase Comparator 2 differ from Phase Comparator 1?

Phase Comparator 1 is an XOR gate that maintains a 90-degree phase shift at the center frequency and requires 50% duty cycle inputs. Phase Comparator 2 uses leading-edge sensing logic to maintain a 0-degree phase shift regardless of duty cycle and features a tri-stateable output.

What is the purpose of the INH (Inhibit) input?

When the INH input is held high, it disables the VCO and all internal op-amps. This feature is designed to minimize standby power consumption when the internal VCO is not being utilized.