Clock/Timing - Clock Generators, PLLs, Frequency Synthesizers

Part Number	Description / PDF	Quantity
STW81102AT STMicroelectronics	IC SYNTHESIZER MULTI RF 28VFQFPN	0
STW81102ATR STMicroelectronics	IC SYNTHESIZER MULTI RF 28VFQFPN	0
STW81200T STMicroelectronics	IC SYNTHESIZER VFQFPN	3702
STW81200TR STMicroelectronics	IC SYNTHESIZER VFQFPN	366
STUW81300T STMicroelectronics	VFQFPN 36 6X6X1.0 PI	2550
STUW81300TR STMicroelectronics	VFQFPN 36 6X6X1.0 PI	2097
STW81101AT STMicroelectronics	IC SYNTHESIZER MULTI RF 28VFQFPN	0
STW81101ATR STMicroelectronics	IC SYNTHESIZER MULTI RF 28VFQFPN	0
HCF4046BEY STMicroelectronics	IC PHASE-LOCK LOOP MCRPWR 16-DIP	0
STW81100ATR-1 STMicroelectronics	IC SYNTHESIZER MULTI RF 28VFQFPN	0
TDA7427D STMicroelectronics	IC SYNTHESIZER/IF COUNTER SO-20	0
HCF4046M013TR STMicroelectronics	IC PHASE-LOCK LOOP MCRPWR 16SOIC	0
TDA7427AD1 STMicroelectronics	IC SYNTHESIZER/IF COUNTER SO-28	0
TDA7427AD1TR STMicroelectronics	IC SYNTHESIZER/IF COUNTER SO-28	0
STW81100AT-1 STMicroelectronics	IC SYNTHESIZER MULTI RF 28VFQFPN	0

Clock/Timing - Clock Generators, PLLs, Frequency Synthesizers

1. Overview

Clock and timing ICs are semiconductor devices that generate, regulate, and distribute timing signals in electronic systems. Key components include Clock Generators (produce stable clock signals), Phase-Locked Loops (PLLs, synchronize signals with phase alignment), and Frequency Synthesizers (generate precise frequencies from reference signals). These devices ensure synchronization across components in modern electronics, enabling reliable operation in communication systems, computing devices, and industrial equipment.

2. Main Types and Functional Classification

Type	Functional Features	Application Examples
Clock Generators	Produce fixed or programmable clock signals with low jitter	Microprocessors, FPGAs, networking equipment
PLLs	Align output signal phase with reference input, enable frequency multiplication	Wireless transceivers, data recovery circuits
Frequency Synthesizers	Generate multiple frequencies from single reference with high precision	5G base stations, satellite communication systems

3. Structure and Components

Typical clock ICs feature: 1) Crystal oscillator interface for reference signal input; 2) Internal voltage-controlled oscillator (VCO); 3) Phase detector and loop filter (PLL components); 4) Programmable dividers; 5) Output buffers. Advanced packages include QFN (4x4mm to 8x8mm) and TSSOP with 8-48 pins. Integration levels vary from single-channel devices to multi-output clock generators with integrated EEPROM.

4. Key Technical Specifications

Parameter	Typical Range	Importance
Frequency Range	1 kHz - 3.6 GHz	Determines application compatibility
Phase Noise	-150 to -120 dBc/Hz	Impacts signal integrity
Jitter (RMS)	50 fs - 1 ps	Critical for high-speed systems
Power Consumption	10-300 mA	Affects thermal design
Temperature Stability	20-100 ppm	Ensures reliability in harsh environments

5. Application Fields

Telecommunications: 5G NR base stations, optical transceivers
Computing: Server motherboards, PCIe clocks
Industrial: Precision test equipment, motor control systems
Automotive: ADAS sensors, infotainment systems
Medical: MRI imaging systems, patient monitoring devices

6. Leading Manufacturers and Products

Manufacturer	Representative Product	Key Features
TI (Texas Instruments)	LMX2594	15-GHz wideband PLL with integrated VCO
Analog Devices	AD9548	4-channel clock generator with 0.1 ppb accuracy
STMicroelectronics	CLK2692	Programmable 2-output synthesizer for automotive
Microchip	ZL30264	High-performance network synchronizer

7. Selection Guidelines

Key selection criteria: 1) Required output frequency and voltage levels; 2) Acceptable phase noise/jitter specifications; 3) Number of required outputs; 4) Operating temperature range; 5) Power budget constraints; 6) Integration level (e.g., single-chip vs. discrete VCO solutions). For wireless applications, prioritize low phase noise. For portable devices, emphasize power efficiency.

8. Industry Trends

Future developments include: 1) Higher integration with on-chip EEPROM and multi-phase outputs; 2) Advancement to sub-10fs jitter performance; 3) Development of radiation-hardened variants for aerospace; 4) Adoption of 3D packaging for reduced EMI; 5) Increased use of AI-enabled dynamic frequency scaling. The market is projected to grow at 7.2% CAGR through 2027 driven by 5G and automotive electrification.