A laminate material creates an insulating layer between two conducting layers. This material conducts very less electricity. FR4 is one of the most common dielectric materials used in PCBs. It is basically a flame-retardant fiberglass reinforced material, which provides a higher heat resistance than a standard PCB. Also, FR-4 possesses an excellent strength-to-weight ratio than other laminates.

When it comes to FR-4 circuit boards, Sierra Assembly has the required expertise, experience, and manufacturing capabilities to provide you quality products required in your industry. We also work with FR-4 high-TG materials. If you require printed circuit boards, which will be subjected to heat, you can always opt for high TG materials.

Standard FR4 Material Properties

At Sierra Assembly, we work with a wide range of FR4 materials, with the following properties:
  • High Decomposition Temperature (Td) (>385 ºC)
  • Normal Glass Transition Temperatures (Tg) ( 130 Tg, 135 Tg, and 140 Tg)
  • High Glass Transition Temperature (Tg) (150Tg or 170Tg)
  • Dielectric Constant (@ 1 GHZ): 4.25 – 4.8
  • Dissipation Factor (@ 1 GHZ): 0.016
  • Low Coefficient of Thermal Expansion (CTE): ((2.5-3.8%))
  • UL Rated ((94V-0, CTI = 3 minimum)
  • Ideal with Standard and Lead-free Assembly

FR4 PCB Capabilities

Our vast industry experience combined with our technical expertise helps us produce customized PCBs that meet client’s expectations. The following capabilities enable us to stay true to our commitment of quality PCBs at shortest turnaround times.
Number of Layers 1-40 layers
Types of PCB Single-sided, Double-sided, and Multilayered
Order Quantity 1-10,000 + pieces
Board Thickness 0.30mm ( Regular), 0.10 ~0.30mm ( Extra Thin)
Board Size Min 6mm x 6mm | Max 500mm x 900mm
Minimum Tracing 3 MIL/MIL
Solder Mask Color White, Green, Black, Blue, Yellow, Red
Hole Diameter Size Normal through hole (diameter >=0.20mm, HDI (diameter <=0.15mm)
Silkscreen Color Black, White, Yellow
Surface Finish OSP- Organic Solderability Preservatives –
RoHS Immersion Tin – RoHS
Immersion Silver – RoHS
HASL – Hot Air Solder Levelling
Lead Free HASL – RoHS
ENIG – Electroless Nickel/Immersion Gold
Radio Frequency (RF) Normal: < 300 Mhz
High Radio Frequency: 300MHz ~ 3GHz
Minimum Drilling Hole Diameter 6 Mil
Minimum Annular Ring 4 Mil
Pre-peg Thicknesses Provided (1080 glass style) 0.0022ʺ
(7628 glass style) 0.0075 ʺ
(2116 glass style) 0.0042ʺ

We, at, Sierra Assembly have built a list of happy and satisfied customers. We value quality above anything. Thus, only high-quality materials are used for assembly. All PCBs undergo rigorous inspection and testing before leaving our premises. This has helped us stay true to our quality commitment. Do you have specific FR4 PCB requirements? Please contact us at the earliest.

Quick Contact


I approached Sierra after being referred to them from another PCB designer. What impressed me was that they were more than willing to take a complex PCB requirement. The PCB assembly they provided was small, lightweight, but provided the amount of power needed for our computer product. Great experience.

- Susan R – Business Computer Industry

I liked Sierra’s quick turn PCB assembly services. They provided a prototype within a few days, and it worked without a hitch. I was extremely satisfied with the quality of the PCB. Their prices are great too.

- Jason G. – Telecom Industry

Sierra Assembly Technology has a great group of people to work with. They are open to almost any request and always get the job done quickly. I’ve been in some tight spots before and needed certain products within a small time window, and Sierra has always been reliable.”

- Richard S. – LED Lighting Manufacturer

Your Partner in Southern California for Circuit Board Assembly Services GET A QUOTE

Sierra Assembly Technology Inc.

10880 Mulberry Ave

Fontana, CA 92337

Phone: 909.355.5400