Dk near 3.15, Df near 0.003 and an operating ceiling around +180°C: a laminate profile for designs that are loss-limited and heat-limited at the same time.
Taconic TLY-3 sits in the middle of a family built for high-frequency work with more thermal headroom than the low-loss grades usually offer. It is specified where a design needs low loss and stable electrical behaviour but also has to survive a hot environment — a combination that rules out many otherwise suitable laminates. This article covers the parameters, the applications and the production process; for the wider brand context, our notes on the performance of Taconic laminates and on competing microwave substrate materials cover the surrounding ground.
The TLY family is Taconic’s answer to designs that need low dielectric loss without the mechanical fragility of pure PTFE. TLY-3 keeps the low-loss platform and raises the usable temperature ceiling, which is why it turns up in aerospace and automotive work where the same board has to face both electrical and thermal requirements. The series also includes grades positioned for other trade-offs, and our notes on the TLY-5 grade as a 5880 alternative show how the family is used when a designer is weighing a substitute for a PTFE reference material.
The headline figure is a Dk of approximately 3.15, held stable across frequency so delay and impedance stay predictable. Df is around 0.003, low enough to keep attenuation under control in high-frequency signal paths. A very low coefficient of thermal expansion maintains dimensions when temperature changes, and the operating range extends to about +180°C at the top end — noticeably higher than comparable grades — with a lower limit near −40°C. Thickness is selectable between roughly 0.076 mm and 0.508 mm, so the same material can serve thin RF layers and thicker structural ones.
| Parameter | Typical value |
|---|---|
| Dielectric constant (Dk) | ≈3.15 |
| Dissipation factor (Df) | ≈0.003 |
| Coefficient of thermal expansion | Very low; stable across a wide temperature range |
| Operating temperature range | −40°C to +180°C |
| Thickness range | 0.003–0.020 in (0.076–0.508 mm) |
| Base construction | High-purity PTFE resin system |
The combination of low loss and a high temperature ceiling opens up applications that a purely low-loss material cannot serve.
Production starts with high-purity PTFE resin, selected for insulation performance, heat resistance and low loss, and combined with other materials to reach the target electrical profile. Composite technology and close process control do the rest: hot pressing, stretching and die-cutting are all managed to keep the dielectric constant and loss values inside tolerance in the microwave band, because those are the properties the customer bought.
Finishing follows conventional practice. Surfaces are metallised to improve solderability and corrosion resistance, with ENIG and OSP the common outcomes — the same options set out in our review of surface treatment for high-frequency boards, where the choice between finishes trades loss, flatness and cost. Quality management then covers each batch for electrical, mechanical and thermal properties, and custom sizes are available for designs that need a specific thickness or panel format.
TLY-3 fits when thermal headroom and low loss are both required. If the design needs the dielectric constant adjusted grade by grade to hit a specific impedance, the TLX series spans Dk from 3.00 to 3.40. If a lower Dk with a similar loss profile suits the circuit better, RF-30 is the closer match. Send us the frequency range, the thermal requirement and the stack-up, and we will confirm which of the three the numbers support.
Frequently Asked Questions
Approximately 3.15, and it holds stable over frequency. Stability is the property that matters for design, because impedance and delay are calculated from Dk and follow it if it drifts.
TLY-3 reaches about +180°C, which is higher than most comparable high-frequency laminates. That extra headroom is what makes it usable in aerospace and automotive electronics.
It needs adjusted process windows rather than a dedicated line. The PTFE base means controlled drilling, via preparation and lamination cycles, so fabricator experience on the family is the practical constraint.
ENIG and OSP are the common choices, selected for solderability and corrosion resistance. Each finish trades loss, flatness and cost differently, so the decision should follow the assembly requirement.
Both sit near Dk 3.0 with low loss. TLY-3 emphasises a higher temperature ceiling, while RF-30 uses ceramic filler for mechanical stability; the choice depends on whether thermal or mechanical margin is tighter.
Send us your frequency plan, temperature requirements and stack-up and we will confirm the grade and the process route.
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