Industrial CMOS Oscillator Family | FCO Standard XO Series

The FCO standard oscillator family integrates a quartz resonator and oscillator circuit into compact SMD packages with CMOS outputs. It’s an efficient choice when you want predictable clock behavior without spending engineering time tuning a discrete crystal loop—especially across multiple clock domains and product variants.

Ready-to-use CMOS clock Industrial temperature options Multiple package footprints Common MHz & 32.768 kHz options

Why engineers choose FCO oscillators in industrial designs:

Reduce BOM complexity by replacing discrete crystal + capacitors with a single XO device.
Provide stable clocks for MCUs, FPGAs, Ethernet PHYs, switches and communication modules.
Improve bring-up speed and repeatability with factory-tested, fixed-frequency outputs.
Support robust operation across temperature and EMI conditions common in industrial environments.

Practical tip: Clock quality is a system result—power integrity, trace routing, and output loading all influence real jitter at the receiving IC.

FCom Fuji Crystal FCO standard CMOS oscillator family for industrial control and embedded systems

Family Overview

The FCO standard oscillator family combines quartz resonators with on-chip oscillator circuits in compact SMD packages. Each device delivers a fixed-frequency CMOS output, factory-programmed to your required system clock. This approach reduces layout sensitivity and helps keep clock behavior consistent across production.

Typical deployments include PLCs and industrial I/O, industrial Ethernet switches, gateways and routers, embedded compute modules (SOM/COM), HMI/display subsystems, protocol conversion and data acquisition equipment—where predictable clocks, fast bring-up and long-term reliability are critical.

Common clock roles in industrial platforms:

SoC/MCU/FPGA reference clocks for control logic and system timing.
Industrial Ethernet clocks for PHYs and switches in gateways, routers and managed switches.
Peripheral clocks for USB, display, communication modules and timing islands.
Low-frequency timing (e.g., 32.768 kHz) for RTC blocks or low-power subsystems when a buffered output is preferred.

Exact frequencies depend on platform requirements; FCO supports a wide range of factory-programmed options.

Application Directions

Industrial systems often operate in noisy electrical environments and across wide temperatures. FCO oscillators are commonly selected where designers want a ready-to-use clock source with predictable behavior for control, networking and embedded computing.

Industrial Control (PLC / I/O / Motion)

Stable MCU/FPGA clocks for deterministic control loops, I/O scan timing, motion profiles and event logging.

Industrial Ethernet & Networking

Clock sources for Ethernet PHYs/switches in gateways, routers and edge devices—supporting reliable link and system timing.

Embedded Compute (Industrial PC / SOM / COM)

Reference clocks for processors and peripherals on embedded platforms used in factory automation and infrastructure.

HMI / Display / Imaging

Pixel clocks and subsystem clocks where jitter control helps maintain signal integrity and stable display performance.

Data Acquisition & Measurement

Clocks for ADC/DSP subsystems where repeatability and low-noise sampling timing improve measurement consistency.

Protocol Conversion & Fieldbus

Stable clocks for communication modules and timing-sensitive interfaces used in industrial connectivity and interoperability.

Key Series and Packages

FCO-3C – 3.2 × 2.5 mm General-Purpose CMOS Oscillator

FCO-3C is a versatile oscillator for many industrial control and embedded platforms:

3.2 × 2.5 mm SMD package suitable for dense control boards and modules.
Wide frequency coverage for common system and peripheral clocks.
Multiple supply options (depending on configuration) such as 1.8 V, 2.5 V and 3.3 V.
CMOS output suitable for typical logic input loads.
Industrial temperature options for harsh environments.

FCO-1C / FCO-2C / FCO-5C / FCO-6C / FCO-7C – Different Footprints

To match PCB density and assembly requirements, the FCO family offers several standard footprints:

FCO-1C – ultra-compact 1.6 × 1.2 mm for space-constrained embedded modules.
FCO-2C – 2.5 × 2.0 mm for mid-density industrial designs.
FCO-5C – larger package for traditional industrial PCBs and easier routing.
FCO-6C – 2.0 × 1.6 mm compact footprint for mixed-signal and RF-adjacent boards.
FCO-7C – 7.0 × 5.0 mm for legacy equipment and layouts preferring larger pads.

Low-Current 32.768 kHz Oscillators (FCO-2K / FCO-6K)

In addition to MHz oscillators, the family includes 32.768 kHz SPXO options for RTC and low-frequency timing:

FCO-2K and FCO-6K – buffered 32.768 kHz outputs for designs that prefer a logic-level RTC reference.
Useful in higher-EMI environments where internal RTC oscillators can be sensitive.
Helps simplify RTC distribution without discrete tuning-fork crystals and external load caps.

Recommended FCom CMOS Oscillator Series

Representative FCO series frequently used in industrial control, networking and embedded platforms:

Series	Package	Typical Clock Use	Recommended Applications	Learn More
FCO-3C	3.2 × 2.5 mm SMD	System & peripheral clocks	Gateways/routers, controllers, industrial PCs and multi-clock designs.	FCO-3C Product Page
FCO-2C	2.5 × 2.0 mm SMD	Embedded module clocks	Compact embedded boards, carrier boards, protocol conversion modules.	FCO-2C Product Page
FCO-5C	Larger SMD	General-purpose clocks	Traditional industrial PCBs and rack equipment with relaxed area constraints.	FCO-5C Product Page
FCO-2K	Low-current SPXO	32.768 kHz RTC output	RTC timing in harsh EMI, buffered logic-level RTC reference.	FCO-2K Product Page
FCO-6K	Low-current SPXO	32.768 kHz RTC output	Dense embedded designs that require a stable RTC clock output.	FCO-6K Product Page

Typical Electrical Performance

While details vary by part number, FCO standard oscillators are commonly selected for:

Factory-programmed frequencies for system, interface and peripheral clock trees.
Common supply options (depending on series), typically spanning low-voltage logic rails.
CMOS output levels compatible with standard MCU/FPGA/PHY inputs.
Jitter behavior aligned with many industrial networking and embedded interface needs.
Stability grades suitable for industrial temperature operation and long service life.

Selection checklist: confirm supply voltage, output enable/standby logic (if any), output load, and the stability/jitter expectations of your receiving IC and interface.

Design Guidelines for Using FCO Oscillators

Simplify the BOM. Replace discrete crystals and capacitors to reduce layout sensitivity and qualification effort.
Pick the right footprint early. Choose package size based on PCB density, assembly flow, and mechanical constraints.
Protect clock quality with power integrity. Place decoupling close to the XO and keep the return path short.
Route the clock like a high-speed net. Keep traces short, avoid stubs, and reference a clean ground plane.
Match grade to environment. Specify temperature range and stability targets for factory floors, outdoor cabinets or infrastructure deployments.

FAQ – Industrial CMOS Oscillator Family

When should I choose an FCO oscillator instead of a discrete crystal?

Choose an FCO oscillator when you want a guaranteed clock output without tuning a discrete oscillator loop, when you need faster design cycles, or when your platform uses multiple clock frequencies across different product variants.

Can FCO oscillators replace existing crystal-based designs without PCB changes?

Often yes. If the selected XO footprint fits your placement and routing constraints, you can remove the discrete crystal and its load capacitors. FCom can help review your clock tree and recommend suitable FCO part numbers.

What should I check first to avoid clock issues in industrial equipment?

Confirm supply voltage and enable pin logic, place decoupling close to the oscillator, keep the clock trace short with a clean return path, and verify the stability and jitter expectations of your interface (MCU/FPGA/PHY/switch).

Need a dependable clock source for industrial control or industrial Ethernet equipment? Share your target frequencies, voltage rails, temperature range and the devices being clocked (MCU/FPGA/PHY/switch). We can recommend an FCO shortlist by footprint and performance grade.

Product Application