Overview
The CD74HC4046A, produced by Texas Instruments, is a high-speed silicon-gate CMOS phase-locked-loop (PLL) circuit. It is part of the HC4046A and HCT4046A series, which are pin compatible with the CD4046B of the '4000B' series. These devices are specified in compliance with JEDEC standard number 7. The CD74HC4046A features a linear voltage-controlled oscillator (VCO) and three different phase comparators, making it versatile for various applications.
Key Specifications
| Parameter | Description | Value |
|---|---|---|
| Operating Frequency Range | Typical at VCC = 5V | Up to 18MHz |
| Minimum Center Frequency | At VCC = 4.5V | 12MHz |
| Operating Power Supply Voltage Range | VCO Section | 3V to 6V |
| Operating Power Supply Voltage Range | Digital Section | 2V to 6V |
| Operating Temperature Range | -55°C to 125°C | |
| Fanout (Over Temperature Range) | Standard Outputs | 10 LSTTL Loads |
| Fanout (Over Temperature Range) | Bus Driver Outputs | 15 LSTTL Loads |
| Input Leakage Current | SIGIN, COMPIN | ±3 to ±45 µA (depending on VCC) |
| High-Level Output Voltage (CMOS Loads) | VCC = 5V | 4.4V (Typ) |
| Low-Level Output Voltage (CMOS Loads) | VCC = 5V | 0.1V (Typ) |
Key Features
- Operating Frequency Range up to 18MHz (Typ) at VCC = 5V
- Choice of three phase comparators: EXCLUSIVE-OR, Edge-Triggered JK Flip-Flop, and Edge-Triggered RS Flip-Flop
- Excellent VCO frequency linearity achieved by linear op-amp techniques
- VCO-Inhibit Control for ON/OFF keying and low standby power consumption
- Minimal frequency drift
- Wide operating temperature range: -55°C to 125°C
- Balanced propagation delay and transition times
- Significant power reduction compared to LSTTL logic ICs
- High noise immunity: NIL = 30%, NIH = 30% of VCC at VCC = 5V
Applications
- FM Modulation and Demodulation
- Frequency Synthesis and Multiplication
- Frequency Discrimination
- Tone Decoding
- Data Synchronization and Conditioning
- Voltage-to-Frequency Conversion
- Motor-Speed Control
Q & A
- What is the typical operating frequency range of the CD74HC4046A at VCC = 5V?
Up to 18MHz.
- What are the three types of phase comparators available in the CD74HC4046A?
EXCLUSIVE-OR, Edge-Triggered JK Flip-Flop, and Edge-Triggered RS Flip-Flop.
- What is the operating power supply voltage range for the VCO section?
3V to 6V.
- What is the operating temperature range of the CD74HC4046A?
-55°C to 125°C.
- How many LSTTL loads can the standard outputs drive over the temperature range?
10 LSTTL loads.
- What is the input leakage current for SIGIN and COMPIN at VCC = 5V?
±3 to ±45 µA (depending on VCC).
- What is the high-level output voltage for CMOS loads at VCC = 5V?
4.4V (Typ).
- What are some common applications of the CD74HC4046A?
FM Modulation and Demodulation, Frequency Synthesis and Multiplication, Frequency Discrimination, Tone Decoding, Data Synchronization and Conditioning, Voltage-to-Frequency Conversion, and Motor-Speed Control.
- How does the VCO-Inhibit Control function in the CD74HC4046A?
The VCO-Inhibit Control is used for ON/OFF keying and to reduce standby power consumption.
- What is the significance of the balanced propagation delay and transition times in the CD74HC4046A?
It ensures consistent and reliable operation across different conditions.
