IC clocks are semiconductor integrated circuits (ICs) that are designed to keep time. IC clocks are important components in virtually all electronic components. They maintain synchronization and timing control in:

• Telecommunications applications
• Consumer electronics
• Wireless handhelds
• Global positioning systems (GPS)

IC clocks may be part of a printed circuit board (PCB) that uses a number of these components. IC clocks can also be used when an input reference clock fails to operate properly. The integrated circuit continues to maintain an accurate clock until the failure of the reference clock is stabilized.

Types

There are two types of IC clocks: silicon-based timing devices and quartz-crystal oscillators.

• Silicon-based IC clocks accurately align a reference clock signal with a clock distribution signal.
• Quartz crystal-based oscillators are also used as timing devices in electronics equipment.

Both silicon-based IC clocks and quartz-crystal IC clocks are used in many applications. Today, an increasing number of semiconductor manufacturers are working to integrate a device’s functions on one chip, which would drive the development of a fully-digital IC clock chip. Semiconductor-based timing devices and phase-locked loop IC clocks are also available. IC clocks that are semiconductor-based include phase-locked loop clock drivers and buffers. A phase-locked loop (PLL) timing device is used in a variety of ways, including for the recovery of clock-timing information from a disk drive, or to maintain timing relationships between processor elements that operate at faster speeds than external signals.

Silicon Labs clock generator for ClockBuilder utility. Video credit: Silicon Labs / CC BY-SA 4.0

Applications

IC clocks are an important electronic component in mobile and handheld devices such as MP3 players, digital cameras, video cameras, handheld gaming systems, mobile phones, home security systems, and global positioning systems (GPS). Digital IC clocks have chips that are used in high-speed data communication devices such as audio multiplexers too. IC clocks can also be used in automotive or industrial applications.

Specifications

IC clocks destined for sale in Europe must comply with RoHS. Reduction of Hazardous Substances (RoHS) is a European Union (EU) directive that requires all manufacturers of electrical and electronic equipment sold in

Europe to demonstrate that their products contain only minimal levels of the following hazardous substances:

• Lead
• Mercury
• Cadmium
• Hexavalent chromium
• Polybrominated biphenyl
• Polybrominated diphenyl ether

Standards

UL 826 - Household electric clocks.

BS EN 60335-2-26 - Household and similar electrical appilcances - safety - Part 2-26: particular requirements for clocks.

Image credits:

Texas Instruments High-Performance Analog | 1-Source Electronic Components