CD74HCT7046AEE4

Overview

The CD74HCT7046AEE4 is a high-speed silicon-gate CMOS phase-locked loop (PLL) circuit manufactured by Texas Instruments. It integrates a linear voltage-controlled oscillator (VCO), two phase comparators, and a lock detector within a single 16-pin PDIP package. The device operates on a digital supply voltage range of 2V to 6V and a VCO supply range of 3V to 6V. It features an Exclusive-OR phase comparator and an edge-triggered JK flip-flop phase comparator. The unit supports a wide operating temperature range from -55°C to +125°C.

Feature Summary

• Integrates a linear voltage-controlled oscillator with excellent frequency linearity and minimal drift.
• Provides two selectable phase comparators: an Exclusive-OR network and an edge-triggered JK flip-flop.
• Includes a dedicated lock detector output that signals a HIGH level when the PLL achieves lock.
• Features a VCO-inhibit control input for ON/OFF keying and low standby power consumption.

Applications

• FM modulation and demodulation
• Frequency synthesis and multiplication
• Tone decoding
• Data synchronization and conditioning

Procurement Notes

Verify the complete part number including the E4 suffix to confirm compliance with environmental standards. Confirm the physical package type matches the design requirements, as this specific model utilizes a 16-lead plastic dual in-line package. Ensure the ordering documentation specifies the full identifier to avoid confusion with non-E4 variants.

Selection Notes

Select the CD74HCT7046AEE4 when direct LSTTL logic compatibility is required due to its HCT technology specifications. This variant is suitable for designs needing a robust lock detector and flexible phase comparison options. Verify that the system power supply aligns with the specified ranges for both the digital section and the VCO section to ensure proper operation.

Part Context

This component belongs to the CD74HC/HCT7046A family of phase-locked loops. The 'E' suffix indicates a 16-lead PDIP package, while the 'M' suffix denotes a SOIC package. The 'EE4' designation specifically identifies the PDIP version with lead-free construction compliant with RoHS directives.

Replacement Considerations

CD74HC7046AE

FAQ

What are the two types of phase comparators available?

The device includes Phase Comparator 1, which is an Exclusive-OR network, and Phase Comparator 2, which is a positive edge-triggered phase and frequency detector based on a JK flip-flop.

How does the VCO-inhibit control function?

Applying a LOW level to the inhibit input enables the VCO, while a HIGH level disables it. This feature allows for ON/OFF keying and helps minimize standby power consumption.

What is the purpose of the lock detector capacitor?

The lock detector capacitor connects between pin 15 (CLD) and pin 8 (Gnd). Its value determines the time constant for detecting the locked condition, filtering glitches, and indicating loss of lock via the output at pin 1.