TLX-8 Microwave PCB | Bicheng PCB

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TLX-8 Microwave PCB

Introduction

Today, we’re going to talk about a type of high volume fiberglass reinforced microwave PCB ----TLX-8 PCB, which offers reliability in a wide range of RF applications. TLX-8 PCBs are ideal for use in radar systems, mobile communications, microwave test equipment and microwave transmission devices.

TLX-8 Typical Properties

Let's dive into the technical specifications and explore what makes this product special.

One of the key features of the TLX-8 is its dielectric constant (DK) at 10 GHz, which is measured to be 2.55. This value indicates the material's ability to store electrical energy in an electromagnetic field. With a DK of 2.55, the TLX-8 offers excellent performance in terms of signal transmission and impedance control.

Next, let's take a look at the dissipation factor (Df) at different frequencies. At 1.9 GHz, the TLX-8 has a Df of 0.0012, and at 10 GHz, it measures at 0.0017. The low Df values indicate minimal loss of signal energy during transmission, ensuring high signal integrity and low signal distortion.

Its dielectric breakdown is more than 45 kilo-voltages and moisture absorption rate features impressively low at 0.02%

Moving on to mechanical properties, the TLX-8 demonstrates impressive strength. It has a flexural strength of 28,900 psi (or 20,600 N/mm2) in the machine direction (MD) and 20,600 psi (or 28,900 N/mm2) in the cross direction (CD). Additionally, the tensile strength is measured at 35,600 psi (or 27,500 N/mm2) in the MD and CD orientations. This robustness ensures the TLX-8 can withstand various mechanical stresses and maintain its structural integrity.

According to ASTM D 902, the material exhibits an elongation at break of 3.94% in the machine direction (MD), indicating its ability to stretch before breaking.

In the cross direction (CD), as per ASTM D 902, the material demonstrates a similar elongation at break of 3.92%, showcasing its flexibility and resistance to tearing.

The material's Young's Modulus is measured to be 980 kpsi (or 1,630 N/mm2) in the machine direction (MD) based on ASTM D 902, indicating its stiffness and resistance to deformation under tension.

Similarly, in the cross direction (CD) following ASTM D 902, the Young's Modulus is determined to be 1,200 kpsi (or 1,200 N/mm2), highlighting its ability to withstand stretching forces.

As per ASTM D 3039, the Young's Modulus in the machine direction (MD) is reported to be 1,630 kpsi (or 1,630 N/mm2), indicating the material's high resistance to deformation in that direction.

The material's Poisson's Ratio, determined according to ASTM D 3039, is found to be 0.135 (or 0.135 N/mm), indicating a slight tendency to contract in the transverse direction when stretched longitudinally.

Then let’s see the peel strength. The data sheet gives us 4 situations: 1oz and half ounces ED copper, 1oz reverse treated copper and 1oz rolled copper. Their peel strengths are very similar to each other. All of them are more than 10 Ibs./linear inch.

The peel strength of the material, evaluated as per IPC-650 2.4.8 Sec.5.2.2 (Thermal Stress), reveals a value of 15 lbs./linear inch (or 17 N/mm) for 1 oz. electrodeposited (ed) material, showcasing its adhesive strength and resistance to delamination under thermal stress conditions.

Similarly, for 1 oz. rolled through hole (RTF) material, the peel strength is determined to be 17 lbs./linear inch (or 17 N/mm), further highlighting its strong bonding properties under thermal stress conditions.

The 1/2 oz. electrodeposited (ed) material demonstrates a peel strength of 14 lbs./linear inch (or 11 N/mm) according to IPC-650 2.4.8.3 (Elevated Temp.), indicating its ability to withstand delamination at elevated temperatures.

Under thermal stress conditions, the peel strength of the 1/2 oz. electrodeposited (ed) material is measured to be 11 lbs./linear inch (or 11 N/mm) as per IPC-650 2.4.8 Sec.5.2.2, suggesting its resistance to delamination even in challenging thermal environments.

The peel strength of 1 oz. rolled material, evaluated according to IPC-650 2.4.8 Sec.5.2.2 (Thermal Stress), is determined to be 13 lbs./linear inch (or 13 N/mm), indicating its ability to maintain adhesion under thermal stress conditions.

In terms of dimensional stability, the TLX-8 exhibits minimal changes even under different conditions. After baking, the dimensional stability is 0.06 mils/in. (or 0.09 mm/M) in the MD direction and 0.08 mils/in. (or 0.1 mm/M) in the CD direction. Similarly, under thermal stress, the TLX-8 maintains its shape with a dimensional stability of 0.09 mils/in. (or 0.09 mm/M) in the MD and 0.1 mils/in. (or 0.1 mm/M) in the CD.

These properties of higher peel strength and lower value in dimensional expansion help the PCB undergo extreme environment at sea or wide range of temperature variation in the flight.

Additionally, the TLX-8 has exceptional electrical properties. It exhibits high surface resistivity, measuring at 6.605 x 10^8 Mohm under elevated temperature conditions and 3.550 x 10^6 Mohm under humidity conditions. Similarly, the volume resistivity is measured at 1.110 x 10^10 Mohm/cm under elevated temperature conditions and 1.046 x 10^10 Mohm/cm under humidity conditions.

Now let's talk about thermal properties. The TLX-8 offers thermal conductivity at 0.19 W/M*K, enabling heat dissipation in electronic applications. It also has a low coefficient of thermal expansion (CTE) of 21 ppm/°C in the X-axis and 23 ppm/°C in the Y-axis, indicating minimal dimensional changes with temperature fluctuations. However, in the Z-axis, the CTE is higher at 215 ppm/°C.

The density (specific gravity) of the material, determined according to ASTM D 792, is reported to be 2.25 g/cm3, indicating its compact and solid nature.

The material demonstrates a temperature at which 2% weight loss occurs (Td) of 535°C as per IPC-650 2.4.24.6 (TGA), indicating its thermal stability and ability to withstand high temperatures.

Similarly, the temperature at which 5% weight loss occurs (Td) is determined to be 553°C according to IPC-650 2.4.24.6 (TGA), further highlightingits resistance to thermal degradation and its ability to maintain its structural integrity at elevated temperatures.

To ensure safety, the TLX-8 has a flammability rating of UL-94 V-0, indicating its high resistance to combustion.

Property	Test Method	Unit	TLX-8 Value	Unit	Value
DK @10 GHz	IPC-650 2.5.5.3		2.55		2.55
Df @1.9 GHz	IPC-650 2.5.5.5.1		0.0012		0.0012
Df @10 GHz	IPC-650 2.5.5.5.1		0.0017		0.0017
Dielectric Breakdown	IPC-650 2.5.6	kV	>45	kV	>45
Moisture Absorption	IPC-650 2.6.2.1	%	0.02	%	0.02
Flexural Strength(MD)	ASTM D 709	psi	28,900	N/mm2
Flexural Strength(CD)	ASTM D 709	psi	20,600	N/mm2
Tensile Strength(MD)	ASTM D 902	psi	35,600	N/mm2
Tensile Strength(CD)	ASTM D 902	psi	27,500	N/mm2
Elongation at Break(MD)	ASTM D 902	%	3.94	%	3.94
Elongation at Break(CD)	ASTM D 902	%	3.92	%	3.92
Young's Modulus(MD)	ASTM D 902	kpsi	980	N/mm2
Young's Modulus(CD)	ASTM D 902	kpsi	1,200	N/mm2
Young's Modulus(MD)	ASTM D 3039	kpsi	1,630	N/mm2
Poisson's Ratio	ASTM D 3039		0.135	N/mm
Peel Stength(1 oz.ed)	IPC-650 2.4.8 Sec.5.2.2(Thermal Stress.)	Ibs./linear inch	15	N/mm
Peel Stength(1 oz.RTF)	IPC-650 2.4.8 Sec.5.2.2(Thermal Stress.)	Ibs./linear inch	17	N/mm
Peel Stength(½ oz.ed)	IPC-650 2.4.8.3(Elevated Temp.)	Ibs./linear inch	14	N/mm

Peel Stength(½ oz.ed)	IPC-650 2.4.8 Sec.5.2.2(Thermal Stress.)	Ibs./linear inch	11	N/mm
Peel Stength(1 oz.rolled)	IPC-650 2.4.8 Sec.5.2.2(Thermal Stress.)	Ibs./linear inch	13	N/mm	2.1
Dimensional Stability(MD)	IPC-650 2.4.39 Sec.5.5(After Bake.)	mils/in.	0.06	mm/M
Dimensional Stability(CD)	IPC-650 2.4.39 Sec.5.4(After Bake.)	mils/in.	0.08	mm/M
Dimensional Stability(MD)	IPC-650 2.4.39 Sec.5.5(Thermal Stress.)	mils/in.	0.09	mm/M
Dimensional Stability(CD)	IPC-650 2.4.39 Sec.5.5(Thermal Stress.)	mils/in.	0.1	mm/M
Surface Resistivity	IPC-650 2.5.17.1 Sec.5.2.1(Elevated Temp.)	Mohm	6.605 x 108	Mohm	6.605 x 108
Surface Resistivity	IPC-650 2.5.17.1 Sec.5.2.1(Humidity Cond.)	Mohm	3.550 x 106	Mohm	3.550 x 106
Volume Resistivity	IPC-650 2.5.17.1 Sec.5.2.1(Elevated Temp.)	Mohm/cm	1.110 x 1010	Mohm/cm	1.110 x 1010
Volume Resistivity	IPC-650 2.5.17.1 Sec.5.2.1(Humidity Cond.)	Mohm/cm	1.046 x 1010	Mohm/cm	1.046 x 1010
Thermal Conductivity	ASTM F433/ASTM 1530-06	W/M*K	0.19	W/M*K	0.19
CTE(X axis)(25-260℃)	IPC-650 2.4.41/ASTM D 3386	ppm/℃	21	ppm/℃	21
CTE(Y axis)(25-260℃)	IPC-650 2.4.41/ASTM D 3386	ppm/℃	23	ppm/℃	23
CTE(Z axis)(25-260℃)	IPC-650 2.4.41/ASTM D 3386	ppm/℃	215	ppm/℃	215
Density(Specific Gravity)	ASTM D 792	g/cm3	2.25	g/cm3	2.25
Td(2% Weight Loss)	IPC-650 2.4.24.6(TGA)	℃	535	℃
Td(5% Weight Loss)	IPC-650 2.4.24.6(TGA)	℃	553	℃
Flammability Rating	UL-94		V-0		V-0

TLX family

There’s TLX-0, TLX-9, TLX-8, TLX-7 and TLX-6 in the TLX family. TLX materials are PTFE-based fiberglass laminates. They are versatile due to its 2.45 - 2.65 DK range and available thicknesses and copper cladding. It is suitable for low layer count microwave designs.

TLX is noteworthy because it is available as a very thin laminate for coupler type applications.TLX-9 has the thinnest thickness of 2mil and TLX-0 has the lowest DK of 2.45

TLX is a workhorse in the world of RF microwave substrates because fiberglass provides mechanical reinforcement wherever they encounter harsh environments.

PCB capability (TLX-58)

For TLX-8 PCBs, we can provide you with single-sided boards, double-sided boards, multi-layer boards and hybrid types. TLX-8 PCBs have wide thickness. These are the standard thickness such as 10 mils, 20 mils, 30 mils and 60mils etc. It’s as thin as 2.5 mils and as thick as 250 mils for our designers.

Finished copper on PCB can be 1oz and 2oz. Our maximum PCB size on TLX-8 is 400mm by 500mm; it can be a single board in the sheet and also can be different designs in this panel.

Solder mask of green, black, blue and yellow etc is available in house. There’s immersion gold, HASL, immersion silver, immersion tin, bare copper and OSP etc. for pads surface finish.

PCB material:	PTFE Fiberglass Laminates
Designation:	TLX-8
Dielectric constant:	2.55
Layer count:	Sinlge-sided PCB, Double-sided PCB, Multi-layer PCB, Hybrid PCB
Dielectric thickness:	2.5mil (0.0635mm), 10mil (0.254mm), 20mil (0.508mm), 25mil (0.635mm), 30mil(0.762mm), 50mil (1.27mm), 60mil (1.524mm), 75mil(1.905mm), 100mil (2.54mm), 125mil (3.175mm), 150mil (3.81mm), 200mil (5.08mm), 250mil (6.35mm)
Copper weight:	1oz (35µm), 2oz (70µm)
PCB size:	≤400mm X 500mm
Solder mask:	Green, Black, Blue, Red, Yellow etc.
Surface finish:	Immersion gold, HASL, Immersion silver, Immersion tin,Bare copper, OSP, ENEPIG, Pure gold etc..

A Piece of TLX-8 PCB

Now on the screen is a type of 1.6mm TLX-8 PCB with immersion gold for the application of filters. TLX-8 PCBs also can be found in radar systems, mobile communications, antennas, mixer, combiners and splitters etc.

TLX-8’s Outgassing Properties

TLX-8 PCB has tightly controlled DK, there’s only ± 2% variation from -55 to 125 °C. It has a long space heritage and is able to experience severe environments such as radiation resistance in space.

From this outgassing test report, we can see total mass loss (TML) of TLX-8 is 0.03%. Collected volatile condensable materials (CVCM) is zero and the amount of water vapor regained (WVR) is 0.01%. These values are very low, which get much higher result than the normal required value.

Property	Test Method	Units	Value
Outgassing (%TML)	ASTM E 595	24 H 257 °F @ ≤ 5 x 10-5 Torr	0.03
Outgassing (%CVCM)	ASTM E 595	24 H 257 °F @ ≤ 5 x 10-5 Torr	0.00
Outgassing (%WVR)	ASTM E 595	24 H 257 °F @ ≤ 5 x 10-5 Torr	0.01

Conclusion

In conclusion, the TLX-8 is an outstanding material that offers a combination of excellent electrical, mechanical, and thermal properties. It provides stable performance in various applications, making it an ideal choice for high-frequency PCB designs, where signal integrity and reliability are paramount.

That wraps up our discussion on the TLX-8 and PCB on it. Thank you for joining us today, and if you have any further questions, feel free to ask our experts. I’ll see you next time.