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XRX-10294
DGXRX
This custom 4-layer FR-4 PCB combines increased routing capacity, dedicated power and ground layers, and a standard 1.6 mm board construction. It is designed for industrial controllers, power supply systems, communication modules, smart appliances, embedded electronics and other applications that require more circuit density than a double-sided PCB.
Compared with more complex 6-layer or HDI designs, a standard 4-layer FR-4 circuit board provides a practical balance between electrical performance, manufacturing complexity and production cost.
XRXPCB supports stack-up review, controlled impedance manufacturing, flying probe testing, PCB fabrication and turnkey PCBA assembly from prototypes to volume production.
Standard 4-Layer FR-4 Construction
Suitable for industrial control, power electronics and embedded systems.
Dedicated Power and Ground Layers
Supports more organized power distribution and signal return paths.
1.6 mm Finished Board Thickness
A widely used construction for standard electronic equipment.
Controlled Impedance Available
Stack-up and trace geometry can be reviewed according to signal requirements.
100% Electrical Testing
Flying probe testing checks the finished PCB for open and short circuits.
PCB and PCBA One-Stop Service
PCB fabrication, component sourcing, SMT assembly, DIP assembly and testing.
Send Your Gerber Files for Stack-Up Review and Quotation
Item | Specification |
|---|---|
Product Type | 4-Layer FR-4 Multilayer PCB |
Layer Count | 4 Layers |
Base Material | FR-4 |
Finished Board Thickness | 1.6 mm |
Copper Weight | Customized according to project requirements |
Surface Finish | Lead-Free HASL, ENIG or OSP |
Solder Mask | Green standard; other colors available |
Silkscreen | White standard; customized colors available |
Via Structure | Plated Through Holes |
Controlled Impedance | Available upon request |
Electrical Testing | Flying Probe Testing |
Production Type | Prototype, Small Batch and Volume Production |
Assembly Service | SMT, DIP and Mixed Assembly |
Final specifications should be confirmed after reviewing the Gerber files, stack-up, copper weight, impedance requirements, minimum trace spacing and hole structure.
A typical 4-layer FR-4 PCB can separate signal routing, ground and power functions across four conductive layers.
Layer | Typical Function |
Layer 1 | Components and Signal Routing |
Layer 2 | Ground Plane |
Layer 3 | Power Plane and Signal Routing |
Layer 4 | Signal Routing and Components |
This structure provides more routing flexibility than a double-sided PCB and allows designers to use internal planes for ground and power distribution.
The final stack-up can be adjusted according to:
Copper weight
Dielectric thickness
Controlled impedance requirements
Signal speed
Current requirements
Thermal management
Component layout
Finished board thickness
A double-sided PCB provides two conductive layers for components, signals, power and ground connections.
A 4-layer PCB adds two internal copper layers, allowing designers to separate signal routing from power and ground distribution. This makes it easier to accommodate MCU circuits, communication interfaces, power management circuits and additional electronic functions.
Internal ground and power planes can provide shorter current return paths and more organized power distribution.
Actual electrical performance depends on the complete stack-up, copper distribution, trace geometry, component placement and circuit design. These factors should be evaluated during the engineering review.
A 4-layer FR-4 PCB is often selected when a double-sided board cannot provide sufficient routing space, but the design does not require the additional layers or advanced via structures of a more complex multilayer PCB.
It provides a practical solution for projects that require:
Increased routing density
Internal power and ground layers
Controlled impedance options
Compact board dimensions
Stable batch production
Reasonable manufacturing complexity
The standard FR-4 material and 4-layer construction make this PCB suitable for engineering prototypes, design validation, small production runs and repeat volume orders.
The same approved stack-up and manufacturing parameters can be maintained across different production batches.
PCB Type | Suitable Applications | Main Characteristics |
Double-Sided PCB | Simple controllers and low-density circuits | Lower complexity but limited routing space |
4-Layer FR-4 PCB | Industrial control, power electronics and embedded systems | Balanced routing capacity, performance and cost |
6-Layer PCB | Higher-density and more complex electronic systems | Additional signal and plane layers with higher manufacturing complexity |
A 4-layer FR-4 PCB is a suitable upgrade when a double-sided design becomes too crowded but a 6-layer or HDI structure is not necessary.
Before production, our engineering team reviews the PCB manufacturing data to identify potential fabrication risks.
The review can include:
Layer sequence and stack-up
Board thickness
Copper weight
Trace width and spacing
Hole size and annular ring
Copper-to-edge clearance
Copper balance
Solder mask clearance
Surface finish
Controlled impedance requirements
Board outline and routing
Panelization design
Any manufacturing concerns can be communicated before fabrication begins, helping reduce unnecessary revisions and production delays.
Controlled impedance is available for suitable 4-layer PCB designs used in communication modules, data interfaces, embedded systems and other signal-sensitive applications.
To evaluate controlled impedance requirements, customers should provide:
Target impedance value
Impedance tolerance
Trace width
Trace spacing
Copper thickness
Reference plane
Differential or single-ended signal requirements
The stack-up and trace geometry will be reviewed before manufacturing.
FR-4 is a glass-reinforced epoxy laminate widely used in rigid printed circuit boards.
It provides a practical combination of:
Mechanical strength
Electrical insulation
Dimensional stability
Moisture resistance
Process compatibility
Material availability
Cost efficiency
FR-4 is suitable for many industrial, consumer, power and communication electronic products.
High-Tg FR-4 material can also be evaluated for projects involving higher operating temperatures, repeated thermal cycles or more demanding assembly processes.
Gerber files, drill files, fabrication drawings and stack-up requirements are reviewed before production.
The engineering team checks whether the design matches the available materials, tolerances and manufacturing processes.
The circuit patterns for the internal copper layers are transferred through imaging and exposure.
Unwanted copper is removed during etching, leaving the required power, ground and signal patterns.
The completed inner layers are inspected before lamination to identify circuit defects, incorrect features or registration issues.
The inner cores, prepreg and outer copper foils are aligned according to the approved stack-up.
Heat and pressure bond the materials into a complete 4-layer PCB structure.
CNC drilling equipment creates component holes, vias, mounting holes and other mechanical features according to the drill files.
Resin residue is removed from the drilled hole walls to prepare the board for copper deposition.
Electroless copper deposition and electrolytic copper plating create conductive connections between the required copper layers.
The outer-layer circuit patterns are transferred, plated and etched to form the final traces, pads and copper areas.
Solder mask protects the copper circuitry and reduces the risk of solder bridging during assembly.
Silkscreen can display component references, polarity marks, product identification and other required information.
The exposed copper pads are protected using a suitable surface finish.
Available options include:
Lead-Free HASL
ENIG
OSP
The appropriate finish should be selected according to component pitch, assembly method, storage requirements and project budget.
Flying probe testing checks the finished boards for open and short circuits before shipment.
Fixture electrical testing can also be evaluated for higher-volume production.
Lead-free HASL is commonly used for industrial controllers, power electronics and general-purpose electronic products.
It provides reliable solderability and is suitable for many standard through-hole and SMT assemblies.
ENIG provides a relatively flat surface and is commonly selected for fine-pitch SMT components, BGA packages and applications requiring improved pad planarity.
OSP applies a thin organic protective coating over exposed copper.
It provides a flat surface and can be considered for suitable assembly processes and controlled storage conditions.
The 4-layer FR-4 PCB can be used in:
PLC control modules
Motor control boards
Automation controllers
Sensor control systems
Industrial monitoring equipment
Human-machine interface controllers
The internal power and ground layers provide additional routing flexibility for control circuits, communication interfaces and power management components.
Typical power-related applications include:
Power supply control boards
DC-DC converter controllers
Charging control boards
Battery management control circuits
Power distribution controllers
Inverter control modules
Copper weight, trace width, thermal vias and allowable temperature rise should be evaluated according to the actual current requirements.
The product can support embedded systems such as:
MCU control boards
IoT gateways
Smart appliance controllers
Data acquisition boards
Embedded communication modules
Sensor interface boards
A customized 4-layer stack-up can support communication products requiring increased routing capacity and controlled impedance.
Applications can include:
Router control modules
Communication interface boards
Network control equipment
Wireless communication modules
Industrial communication gateways
AOI can inspect circuit patterns for defects such as:
Open traces
Short circuits
Missing copper
Excess copper
Incorrect pads
Trace width abnormalities
Flying probe testing checks the electrical continuity of prototypes and small production batches without requiring a dedicated test fixture.
Board dimensions, hole positions, routed slots, outline tolerances and other mechanical features are inspected according to the fabrication data.
Hole diameter, plating condition and hole-wall copper quality can be checked according to the project requirements.
Cross-section analysis can be arranged for selected projects to evaluate layer registration, hole-wall plating and internal PCB structure.
XRXPCB provides integrated PCB and PCBA manufacturing services.
Available services include:
PCB fabrication
BOM review
Component sourcing
SMT assembly
Through-hole assembly
DIP assembly
BGA assembly
AOI inspection
X-ray inspection
Functional testing
Cable assembly
Box-build integration
Combining PCB production and assembly helps reduce communication gaps between board fabrication, component purchasing and assembly.
Please provide the following information when requesting a quotation:
Gerber files
NC drill files
Layer count
Required quantity
Finished board thickness
Copper weight
Surface finish
Solder mask color
Silkscreen color
Controlled impedance requirements
Electrical testing requirements
Panelization requirements
Special tolerances
BOM for PCBA orders
Pick-and-place files
Assembly drawings
Complete manufacturing data allows the engineering team to evaluate the design and prepare a more accurate quotation.
A 4-layer FR-4 PCB contains four conductive copper layers separated by insulating FR-4 materials.
A common construction uses two outer signal layers and two inner layers for ground, power or additional signal routing.
A 4-layer PCB is suitable when a double-sided design does not provide enough routing space or when the circuit requires dedicated power and ground layers.
It is commonly used for MCU circuits, communication interfaces, power controllers and embedded electronic systems.
A finished thickness of 1.6 mm is widely used for rigid printed circuit boards.
Other board thicknesses may be available according to the required stack-up, copper weight and project design.
Yes. Controlled impedance can be manufactured when the stack-up, dielectric thickness, copper thickness and trace geometry are properly defined.
Customers should provide the required impedance value and tolerance during the quotation stage.
Lead-free HASL is suitable for many standard industrial and power applications.
ENIG is commonly selected for fine-pitch components and applications requiring a flatter pad surface.
OSP can be considered for suitable assembly processes that require a flat copper surface.
Yes. XRXPCB provides PCB fabrication, component sourcing, SMT assembly, DIP assembly, inspection and functional testing according to customer requirements.
Yes. Prototype, small-batch and volume production services are available.
Flying probe testing is commonly used for prototypes and small production quantities.
