PCB - Double Sided

Description

A double-sided printed circuit board (PCB) is a PCB with copper foil patterns formed on both the top and bottom surfaces. The circuits on both surfaces are electrically connected via vias, allowing for higher circuit density and design flexibility than single-sided PCBs. A double-sided PCB is a PCB structure that places circuits on both the top and bottom surfaces, offering higher circuit density and design flexibility than single-sided PCBs.

Specifications

Base Material
Key factors determining the mechanical strength, electrical properties, and price of single-sided PCBs.

FR-4
• Glass fiber-based epoxy resin
• Excellent strength, heat resistance, and moisture resistance
• Suitable for industrial and high-reliability products

CEM-3
• Cost-effective compared to FR-4
• Suitable for products requiring medium reliability

Recommended
Most double-sided PCBs use FR-4.

Board Thickness
• Typical range: 0.6 mm ~ 3.2 mm
• Most used:1.6 mm

Selection Criteria
• Small and lightweight: 0.8 to 1.2 mm
• Mechanical rigidity and vibration requirements: 1.6 mm or more

Copper Weight
• General Specifications: 1 oz / 2 oz (per ft²)
• Directly affects current capacity and heat dissipation characteristics

Selection criteria
• Signal/Control Circuits: 1 oz
• Power/High-Current Lines: 2 oz or more

Lines & Spaces
• Standard Specification: 150–200 μm
• Minimum Possible Specification: 100 μm

Double-sided PCBs utilize vias to distribute wiring, making it easier to implement finer patterns than single-sided PCBs.

Layer Count
• 2 Layer(Top / Bottom)
Multilayer PCBs may be more suitable for high-speed, high-frequency circuits because power and signal separation is limited.

Via specifications
Through Hole Via(PTH)
• For upper and lower electrical connections
• Drill size and plating quality are critical to reliability

Surface Finish
Solderability, Storabiity, and cost are affected.

LF HASL(Lead-Free HASL)
• Excellent solderability for the price
• Most widely used

OSP
• Low cost and environmental friendliness
• Suitable for short-term use

Im Tin / Im Silver
• Excellent flatness
• Mid-end specifications

ENIG
• Excellent reliability and flatness
• Relatively high cost

Recommendation
General double-sided PCBs → LF HASL / OSP.

Solder Mask
Responsible for circuit protection and appearance quality.

Colors
• Green, White, Black, Blue, Red, Yellow

Green is the most stable and cost-effective

Electrical Test
BBT(Bare Board Test)
• Open/Short Inspection
• Full inspection is recommended even on double-sided PCBs.

Technical Data

Item	General Specifications
Board Material	FR-4, CEM-3
Thickness	0.6 ~ 3.2 mm (1.6 mm standard)
Copper Foil	1~2 oz
Line WIdth/Pitch	150~200 μm (Minimum 100 μm)
Layer	2
Surface Finish	LF HASL, OSP recommended
Solder Mask	Green and others
Test	BBT(Open/Short)