Texas Instruments CD74HC4046APW

Overview

CD74HC4046APW from Texas Instruments is a high-speed CMOS phase-locked loop (PLL) IC integrating a linear voltage-controlled oscillator (VCO) and three selectable phase comparators (XOR, edge-triggered JK, edge-triggered RS). It operates from 2V to 6V, achieves up to 18MHz typical VCO frequency at 5V, supports –55°C to +125°C operation, and features VCO-inhibit control for low standby power-used in FM demodulation, frequency synthesis, and motor-speed control.

For engineers reviewing the CD74HC4046APW datasheet, CD74HC4046APW pinout, CD74HC4046APW application, or CD74HC4046APW equivalent, this page delivers verified functional identity, validated TSSOP-16 pin mapping, confirmed VCO linearity (≤0.4% deviation), exact comparator transfer functions, and real-world PLL design constraints including R1/C1 dependency, DEMOUT voltage fidelity, and INH-driven VCO enable/disable behavior.

Technical Context

The CD74HC4046APW implements a second-order PLL architecture using an op-amp-based linear VCO whose center frequency is set by external R1, R2, and C1 components; DEMOUT provides a buffered, offset-compensated replica of VCOIN with ≤±20mV error at 4.5V. Its three phase comparators operate independently: PC1 (XOR) requires 50% duty-cycle inputs and yields VDEMOUT = (VCC/π)(φSIGIN − φCOMPIN); PC2 (edge-triggered JK) delivers three-state UP/DOWN outputs and lock-indication via PCPOUT HIGH.

PC3 (edge-triggered RS) produces frequency-difference output VDEMOUT = (VCC/2π)(fSIGIN − fCOMPIN), enabling wide capture range without low-pass filter dependency. All digital sections comply with HC logic thresholds (VIH ≥ 3.15V, VIL ≤ 1.35V at VCC = 4.5V), while VCO section tolerates 3V–6V supply-enabling mixed-voltage system integration with independent analog/digital rail optimization.

Key Specifications

Pinout & Package

CD74HC4046APW uses a 16-pin TSSOP package (PW suffix), 4.4mm × 5mm body, 0.65mm pitch, with exposed pad optional per TI design guidelines.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar phase-locked loop applications.

Compared with CD74HC4046APW, CD74HCT4046APW maintains full functional equivalence with TTL input compatibility, while SN74LV4046AIPW trades comparator flexibility and VCO bandwidth for lower-voltage operation and faster digital timing-making CD74HC4046APW the optimal choice for mixed-voltage, wide-frequency, multi-comparator PLL designs.

Availability

CD74HC4046APW is available at Aetrix Electronics and suitable for FM demodulation, frequency synthesis, and motor-speed control applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HC4046APW includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic solutions with over 50 years of innovation in high-reliability timing and control ICs.

The CD74HC4046A belongs to TI's legacy HC logic family, designed specifically for robust, wide-temperature PLL implementations in industrial, aerospace, and instrumentation systems where VCO linearity, comparator flexibility, and supply resilience are critical.

FAQ

What is the maximum operating frequency of the CD74HC4046APW VCO?

The CD74HC4046APW VCO achieves a maximum frequency of 24 MHz at VCC = 4.5V with C1 = 50pF and R1 = 3.5kΩ. At VCC = 6V and C1 = 0pF, it reaches 38 MHz. These values are measured under specified test conditions and assume proper external component selection and PCB layout for minimal parasitic capacitance.

How does the DEMOUT pin function in the CD74HC4046APW?

The DEMOUT pin in the CD74HC4046APW provides a buffered, low-offset replica of the VCOIN control voltage, with ≤±20mV error at VCC = 4.5V. Unlike conventional designs, DEMOUT equals VCOIN rather than being offset by one threshold voltage-enabling direct use in loop filters without compensation. A load resistor (RS) of 50kΩ–300kΩ must be connected to GND if DEMOUT is used.

Which phase comparator should I use for data synchronization in the CD74HC4046APW?

For data synchronization, Phase Comparator 2 (PC2) is recommended in the CD74HC4046APW. Its edge-triggered JK flip-flop architecture delivers three-state UP/DOWN outputs, supports arbitrary input duty cycles, and provides a reliable PCPOUT HIGH signal during lock-making it ideal for recovering clock and data from serial streams with variable edge timing.

Can the CD74HC4046APW operate from a 3.3V supply?

Yes, the CD74HC4046APW operates from 2V to 6V for its digital section and 3V to 6V for its VCO section. At 3.3V, the VCO center frequency is ~7–10 MHz (depending on R1/C1), and PC1/PC2 propagation delays increase to ~200ns/265ns respectively. Ensure external R1 ≥ 3kΩ and C1 ≥ 40pF for stable operation within datasheet limits.

What is the purpose of the INH pin on the CD74HC4046APW?

The INH (Inhibit) pin on the CD74HC4046APW is an active-HIGH control that disables both the VCO and DEMOUT circuits, reducing quiescent current to ≤160 µA across –55°C to +125°C. This feature enables low-power standby modes in battery-operated systems such as portable sensors or remote telemetry units without requiring full device power-down.