Good to Know Information about Single-Double-Sided Rigid PCBs

PCBs have been used in electronic and electromechanical devices since decades. However, the older and simpler devices had single-sided PCBs, which are not compatible for the new-age, slim, smart, and miniature devices. Single-sided PCBs are the most basic and old forms of PCBs, used in simple devices. They have only one layer of conductive material. Double-sided PCBs are a slightly advanced version of the former. As the term suggests, there are layers of conductive material on both the sides of the board. It is used in communication devices and other technologically advanced instruments. Now, there are multilayered PCBs too. This post, however, discusses the details of single- and double-sided PCBs, their designs, applications, and advantages.

An Introduction to Single-Sided PCB Design

As mentioned, this type of PCB has a fairly simple design and is used in relatively simple devices. Unlike a double-sided PCB, cross circuitry is not possible here. The substrate here is usually made of FR4, fiberglass or aluminum, which is laminated with a copper layer. The thickness of these PCBs may range between 0.4mm and 3.5mm, including the copper coating and soldering. The stack up of a PCB comprises how the copper and insulation material layers are arranged prior to the PCB design. A PCB layer stack helps avoid noise and impedance. So, in single-sided PCBs, the stack up is only of one material, and hence a stack up may not be required for most applications.

Here is a basic design of a single-sided PCB.

Solder Mask
Copper Layer
Substrate or Dielectric Layer

Know How a Double-Sided PCB Design Differs from Single-Sided PCB

As mentioned, they have layers of conductive material on both the layers. This type of PCB enables alternating between both the layers using via routes. This is the basic design of a double-sided PCB.

Solder Mask
Copper Layer
Dielectric Layer
Copper Layer
Solder Mask

So, there is a top layer and a bottom layer. Usually, the substrate material is made of fiber glass with a copper lamination on it. This increases the conductivity and keeps it even throughout the board. This type of PCB enables drilling of holes that allows circuits on either ends to be connected to the ones at the opposite end. The stack up is really required from four layers onward, and hence may not be a prerequisite for all double-sided PCB designs. To reduce electromagnetic interference (EMI) in these type of PCBs, the wiring loop is reduced, and that suffices. The standard thickness of this two-layer PCB ranges between 1.2mm and 1.7mm. The overall PCB thickness includes the actual PCB, copper layer, and soldering mask.

Applications of Single-Sided and Double-Sided PCBs

There are many applications of both these types of PCBs. Here are a few of the applications of single-sided PCBs:

  • Relays
  • Sensors
  • Camera systems
  • Vending machines
  • Surveillance equipment
  • Calculators
  • Timer circuits

Here are a few applications of double-sided PCBs:

  • Relay systems
  • UPS systems
  • HVAC systems
  • Traffic control systems
  • Vending machines
  • LED lighting systems
  • Printers
  • Hard drives
  • Regulators

Benefits of Single-Sided and Double-Sided PCBs

Despite advancements in PCB technology, single-sided PCBs still exist, and offer a lot of benefits. Here are a few benefits of single-sided PCBs:

  • They are cost effective.
  • They are good for basic applications and also for amateurs, starters, and enthusiasts in this industry who want to develop their own PCB-embedded device.
  • They can be designed quickly, and are useful for high-volume productions.

Double-sided PCBs certainly have an edge over single-sided PCBs when it comes to usability in slightly complex devices. Here are a few benefits of double-sided PCBs:

  • These are certainly more flexible than single-sided PCBs in terms of design.
  • You can make them compact, and reduce the board size, and in turn the overall cost.
  • They increase the circuit density because of the double layer, although they are not meant for extremely complex circuits.
  • They are excellent for medium level of complexity in circuits.