NXP Semiconductors 74HC4046ADB,112

Overview

74HC4046ADB,112 from NXP Semiconductors 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 delivers up to 17 MHz VCO center frequency at 5 V, supports 3.0–6.0 V VCO supply and 2.0–6.0 V digital logic supply, and enables FM demodulation, frequency synthesis, and motor-speed control in industrial timing systems.

For engineers reviewing the 74HC4046ADB,112 datasheet, 74HC4046ADB,112 pinout, 74HC4046ADB,112 application, or 74HC4046ADB,112 equivalent, key selection criteria include VCO linearity (≤0.4% at 4.5 V), phase comparator gain differences (K_p = V_CC/π for PC1, V_CC/4π for PC2), DEMOUT voltage tracking fidelity (±20 mV offset), and INH input compatibility with HC-level logic (VIH ≥ 2.1 V at 3 V).

Technical Context

The 74HC4046ADB,112 implements a second-order PLL architecture using external passive components: C1 (40 pF min) between pins 6–7 and R1 (3–300 kΩ) from pin 11 to GND sets VCO frequency range, while optional R2 (pin 12) introduces frequency offset. Its VCO features op-amp buffered input (VVCOIN 1.1–3.4 V at 4.5 V), 50% duty-cycle output (±1%), and low temperature drift (0.15 %/K).

All three phase comparators share SIGIN (pin 14) and COMPIN (pin 3) inputs but differ fundamentally: PC1 (XOR) requires 50% duty signals and yields maximum lock range only with ripple suppression; PC2 (edge-triggered D-flip-flop) provides frequency/phase detection with 3-state output and lock-detection via PCPOUT (pin 1); PC3 (RS flip-flop) offers wider phase response (0°–360°) but higher ripple content.

Key Specifications

Pinout & Package

74HC4046ADB,112 is supplied in a 16-pin SO (Small Outline) package per JEDEC MS-012AC, 3.9 mm body width, 1.27 mm pitch. Pin 1 is marked by a beveled corner or dot; pin numbering follows standard counter-clockwise sequence from top-left when viewed with marking side up.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD4046BE and SN74LV4046A, the 74HC4046ADB,112 uniquely balances 17 MHz VCO speed, three-phase-comparator flexibility, and robust 5 V system compatibility - making it optimal for FM demodulation and frequency synthesis where both performance and design maturity matter.

Availability

74HC4046ADB,112 is available at Aetrix Electronics and suitable for FM demodulation, frequency synthesis, and motor-speed control applications requiring stable component supply across industrial temperature ranges (−40 °C to +125 °C).

Supply support for 74HC4046ADB,112 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

NXP Semiconductors is a global semiconductor leader specializing in secure connectivity solutions for automotive, industrial, and IoT applications, with roots in Philips' semiconductor division.

The 74HC4046ADB,112 belongs to NXP's 74HC logic family, designed specifically for high-speed, low-power PLL implementations in timing-critical systems where VCO linearity, phase comparator choice, and supply flexibility are essential.

FAQ

What is the maximum VCO center frequency achievable with the 74HC4046ADB,112?

The 74HC4046ADB,112 achieves a typical VCO center frequency of 17 MHz at V_CC = 4.5 V, R1 = 3 kΩ, and C1 = 40 pF. This value is confirmed in the Quick Reference Data table on page 4 of the official datasheet. Higher frequencies require smaller C1 values (≥40 pF minimum) and lower R1, but stability and temperature drift must be verified per Figures 19 and 21.

How does the DEMOUT pin function in the 74HC4046ADB,112, and why is it valuable?

The DEMOUT pin (10) in the 74HC4046ADB,112 provides a buffered, low-impedance replica of the VCOIN voltage with ±20 mV offset at 4.5 V. Unlike conventional demodulators, DEMOUT equals VCOIN rather than being offset by one threshold voltage - enabling direct use in feedback loops without additional op-amps. This feature is explicitly documented in the General Description and DC Characteristics sections.

Which phase comparator should I select for frequency acquisition in noisy environments using the 74HC4046ADB,112?

For frequency acquisition in noisy environments, PC2 (pin 13) is recommended in the 74HC4046ADB,112. As described in the Phase Comparator 2 section, PC2 functions as an up-down counter that maintains lock even with harmonic-rich or jittery inputs, and its 3-state output minimizes low-pass filter power dissipation. The datasheet confirms PC2's superior capture behavior versus PC1 and PC3 under noise.

Can the 74HC4046ADB,112 operate with separate analog and digital supplies?

No - the 74HC4046ADB,112 uses a single V_CC pin (16) powering both digital comparators and the analog VCO section. However, the datasheet specifies different operational voltage ranges: the VCO section requires 3.0–6.0 V, while the digital section functions from 2.0–6.0 V. This means the part can operate down to 3.0 V total supply, but cannot isolate analog/digital domains with independent rails.

What external components are mandatory for basic 74HC4046ADB,112 PLL operation?

For basic 74HC4046ADB,112 PLL operation, two external components are mandatory: capacitor C1 (≥40 pF) connected between pins 6 and 7, and resistor R1 (3–300 kΩ) connected from pin 11 to GND. These set the VCO frequency range. Optional R2 (pin 12) adds frequency offset, and a low-pass filter (e.g., RC network) is required between PCnOUT and VCOIN to close the loop - all specified in the General Description and Application Information sections.