TC350 Plus is a reinforced ceramic-filled PTFE development with a higher reported through-thickness thermal conductivity and different dielectric data from TC350. It is relevant to RF power circuits where substrate heat transfer and low electrical loss are jointly important. The Plus suffix therefore deserves a separate model and manufacturing review.
Material system
Ceramic-filled PTFE reinforced with woven glass
Technical properties
| Property | Reported value | Conditions / source |
|---|---|---|
| Process dielectric constant | 3.5 | Typical, 10 GHz, 23°C; IPC-TM-650 2.5.5.5 clamped stripline; direction is not separately recorded here. Source |
| Design dielectric constant | 3.62 | Typical; 10 GHz, microstrip differential phase length method, C-24/23/50 conditioning. Source |
| Dissipation factor | 0.0017 | Typical, 10 GHz, 23°C; IPC-TM-650 2.5.5.5; direction is not separately recorded here. Source |
| Thermal conductivity | 1.24 W/(m·K) | Typical, through thickness; ASTM D5470. The product table does not state test temperature. Source |
| CTE, X axis | 10 ppm/°C | Typical; -55°C to 288°C, IPC-TM-650 2.4.41; average expansion over the interval, not necessarily linear. Source |
| CTE, Y axis | 9 ppm/°C | Typical; -55°C to 288°C, IPC-TM-650 2.4.41; average expansion over the interval, not necessarily linear. Source |
| CTE, Z axis | 38 ppm/°C | Typical; -55°C to 288°C, IPC-TM-650 2.4.41; average expansion over the interval, not necessarily linear. Source |
| Thermal coefficient of dielectric constant | -42 ppm/°C | Typical; 50°C to 150°C, IPC-TM-650 2.5.5.5 (modified temperature measurement); 10 GHz. Source |
| Water absorption | 0.05 % | Typical; E1/105 + D48/50, IPC-TM-650 2.6.2.1. Source |
| Density | 2.22 g/cm³ | Typical; C-24/23/50, ASTM D792. Source |
Typical reported values are not a purchase specification. Process Dk, design Dk and values measured at different frequencies are not interchangeable.
Selection and design notes
- Use it when the dielectric is a meaningful part of the heat path and the required line geometry fits its permittivity. Compare the whole assembly's thermal resistance, including bondline and carrier, before paying for a material change.
- For a power divider, evaluate conductor loss and temperature together. Heating can be generated in copper as well as dielectric, and a smoother foil can affect both electrical and thermal behavior.
Thickness and copper options
Standard cores include 10, 20, 30 and 60 mil; other increments are described as enquiries rather than guaranteed stock.
Reverse-treated ED copper is listed. The published smooth-foil characteristic belongs to the specified foil construction.
Fabrication considerations
- Discuss the filled-PTFE drilling process and the selected reverse-treated foil with the fabricator. The standard thickness range supports several RF geometries; choose it using both impedance and mechanical constraints rather than a thermal number alone.
Application fit
- High-power RF networks
- Industrial RF heating
- Microwave amplifiers
Limits and substitution checks
- The product datasheet's moisture conditioning and density are more specific than the selector's older summary. The reported conductivity is a material measurement, not a system temperature prediction. A claim of improved drilling does not replace process qualification for the actual hole size, tool and stack.