Thermoset laminate materials, including FR-4, are affected by oxidation over time and temperature. This can slightly increase the dielectric constant and dissipation factor of the circuit substrate. The change rate and impact on circuit performance vary based on design and operating temperature. Rogers’ RO4835™ laminate, part of the RO4000® series, offers enhanced stability at high temperatures and is more resistant to oxidation than other hydrocarbon materials. RO4835 laminates share similar electrical and mechanical properties with RO4350B™ laminates and are designed for high frequency PCB performance and cost-effective circuit fabrication. It uses standard epoxy/glass (FR-4) processes and is competitively priced.
For frequencies above 500 MHz, RO4000 materials are ideal due to their low dielectric loss, making them suitable for RF microwave circuits and controlled impedance transmission lines. The material’s thermal coefficient of expansion (CTE) matches copper, ensuring excellent dimensional stability and reliable
plated through-hole quality in mixed dielectric multi-layer boards, even under thermal shock. RO4000 laminates have aTg of >280°C (536°F), ensuring stable expansion characteristics throughout circuit processing temperatures.
RO4000 series laminates can be processed using standard FR-4 techniques without specialized via preparation. They are rigid, thermoset laminates, compatible with automated systems and scrubbing equipment for copper surface preparation. RO4835 laminates are RoHS compliant and suitable for UL 94V-0 certified applications.
Features and Benefits:
Significantly improved oxidation resistance compared to typical thermoset microwave materials
• Designed for performance sensitive, high volume applications.
Low loss
• Excellent electrical performance allows application with higher operating frequencies.
• Ideal for automotive applications.
Tight dielectric constant tolerance
• Controlled impedance transmission lines
Lead-free process compatible
• No blistering or delamination
Low Z-axis expansion
• Reliable plated through holes
Low in-plane expansion coefficient
• Remains stable over an entire range of circuit processing temperatures
CAF resistant
Typical Applications:
• Automotive Radar and Sensors
• Point-to point Microwave
• Power Amplifiers
• Phased – Array Radar
• RF Components
Standard Offerings
| Standard Thicknesses | Standard Panel Sizes | Standard Cladding |
| 0.0066” (0.17mm) +/- 0.0007” 0.010” (0.25mm) +/- 0.0010” 0.020” (0.51mm) +/- 0.0015” 0.030” (0.76mm) +/- 0.0020” 0.060” (1.52mm) +/- 0.0040” |
12” X 18” (305 X 457 mm) 24” X 18” (610 X 457 mm) 24” X 36” (610 X 915 mm) 48” X 36” (1219 X 915 mm) |
Electrodeposited Copper Foil 1/2 oz. (18μm) 1 oz. (35μm) |
RO4835 LAMINATES
Standard Properties Table
| Properties | Typical Value | Units | Test Conditions | Test Method | ||
| Electrical Properties | ||||||
| Dielectric Constant (Process)1 | 3.48 ± 0.05 | – | 23˚C | 10 GHz | IPC TM-650 2.5.5.5 | |
| Dielectric Constant (Design)2 | 3.66 | – | – | 8 – 40 GHz | Differential Phase Length | |
| Dissipation Factor | 0.0037 | – | 23˚C | 10 GHz | IPC TM-650 2.5.5.5 | |
| Thermal Coefficient of Dielectric Constant | +50 | ppm/°C | -50°C to 150°C | IPC TM-650 2.5.5.5 | ||
| Volume Resistivity | 5 X 108 | MΩ•cm | Condition A | IPC-TM-650, 2.5.17.1 | ||
| Surface Resistivity | 7 X 108 | MΩ | ||||
| Electrical Strength (dielectric strength) | 30.2 (755) | KV/mm (V/mil ) | – | IPC TM-650 2.5.6.2 | ||
| Thermal Properties | ||||||
| Decomposition Temp (Td) | 390 | ˚CTGA | – | ASTM D3850 | ||
| Glass Transition Temp (Tg) | >280 | ˚CTMA | A | IPC-TM-650 2.4.24.3 | ||
| Coefficient of Thermal Expansion – x | 10 | ppm/˚C | -55˚C to 288˚C | IPC TM-650 2.4.41 | ||
| Coefficient of Thermal Expansion – y | 12 | |||||
| Coefficient of Thermal Expansion – z | 31 | |||||
| Thermal Conductivity | 0.66 | W/(m.K) | 80˚C | ASTM C518 | ||
| Dimensional Stability (x,y) | <0.5 | mm/m (mils/in) | after etch | +E2/150°C | IPC TM-650 2.4.39a | |
| Mechanical Properties | ||||||
| Copper Peel Strength | 0.88 (5.0) | N/mm (pli) | After solder float 35 μm ED foil | IPC TM-650 2.4.8 | ||
| Young’s Modulus | 7780 (1128) | MPa (kpsi) | RT | ASTM D638 | ||
| Tensile Strength | 136 (19.7) | MPa (kpsi) | RT | ASTM D638 | ||
| Flexural Strength | 186 (27) | MPa (kpsi) | IPC-TM-650 2.4.4 | |||
| Physical Properties | ||||||
| Flammability | V-0 | UL 94 | ||||
| Moisture Absorption | 0.05 | % | 50˚C | 48 Hr | ATSM D570 | |
| Density | 1.92 | g/cm³ | 23˚C | ASTM D792 | ||
| Lead Free Process compatible | YES | – | – | – | ||
