Taconic TLY-3 PCB: Properties, Design & Fab

What Is the Taconic TLY-3 PCB Laminate?

Taconic TLY-3 is a woven-fiberglass-reinforced PTFE laminate with a dielectric constant (Dk) of 2.33 ± 0.02 and a dissipation factor (Df) of 0.0009 at 10 GHz. Engineers choose a Taconic TLY-3 PCB for microstrip circuits, feed networks and filter designs from L-band through Ka-band (up to roughly 40 GHz) because of its ultra-low loss tangent and tight Dk tolerance. If you need a dimensionally stable, low-Dk PTFE board that machines and plates reliably, TLY-3 sits in the sweet spot between commodity PTFE laminates and exotic ceramic-filled options.

Key Material Properties of Taconic TLY-3

The table below collects the electrical, thermal and mechanical parameters that matter most when you are evaluating a Taconic TLY-3 PCB against alternatives such as Rogers RT/duroid 5870 or other Taconic grades.

A Dk of 2.33 is among the lowest you can get in a glass-reinforced PTFE. Lower Dk means wider traces for the same impedance target, which relaxes fabrication tolerances and reduces conductor loss at millimeter-wave frequencies. The trade-off is that wider traces consume more board area—an issue in dense phased-array layouts where a slightly higher-Dk material such as Taconic TLC-32 with Dk 3.20 may save real estate.

Comparing the Taconic TLY-3 PCB with Related Laminates

Choosing a PTFE laminate is rarely about a single parameter. The table below puts TLY-3 alongside materials engineers frequently evaluate in the same design cycle.

TLY-3 and RT/duroid 5870 share the same Dk, but TLY-3’s woven-glass reinforcement gives it better dimensional stability during drilling and routing, while 5870’s random microfiber construction can yield a more isotropic Dk in the x-y plane. For designs where Dk isotropy matters less than mechanical repeatability—think high-volume panel processing—TLY-3 often wins on yield.

If your project demands an even lower loss tangent at millimeter-wave bands, consider Taconic TSM-DF, which targets ultra-low-loss multilayer builds. For budget-friendly sub-6 GHz work, Taconic RF-35 is a proven alternative.

Use the selector below to compare TLY-3 against the full Taconic portfolio by Dk range, loss and frequency band.

Dk Stability and Drift in Taconic TLY-3 PCB Designs

PTFE substrates are prized for Dk stability, but no dielectric is perfectly constant across temperature, frequency and moisture. TLY-3’s thermal coefficient of Dk is typically −80 ppm/°C, meaning Dk drops slightly as the board heats up. Over a 100 °C swing (−40 °C to +60 °C ambient), that translates to roughly a 0.019 shift—small, but enough to move a narrowband filter’s center frequency by a fraction of a percent.

Moisture absorption below 0.02 % keeps humidity-driven Dk drift negligible in most environments, a clear advantage over hydrocarbon ceramic laminates that can absorb 0.1 % or more.

Enter your operating temperature range and nominal Dk below to estimate the effective Dk shift for your Taconic TLY-3 PCB design.

For a TLY-3 board operating from −40 °C to +85 °C, the estimator will show roughly ±0.01 of Dk variation. In a 10 GHz bandpass filter on 20-mil (0.508 mm) TLY-3, that corresponds to about 4–5 MHz of center-frequency shift—well within typical tuning margin. If your link budget cannot tolerate even that, consider adding a temperature-compensation network or switching to a ceramic-loaded PTFE with a near-zero thermal coefficient of Dk.

Fabrication Guidelines for Taconic TLY-3 PCB Builds

Drilling and Routing

PTFE is softer than FR-4 and tends to smear during drilling. Use carbide drill bits with a positive rake angle, reduce spindle speed to 40,000–60,000 RPM (versus 80,000+ for FR-4), and keep chip loads moderate. Back-up boards should be rigid aluminum or phenolic to prevent exit burrs. For via diameters below 10 mil (0.254 mm), laser drilling with a CO₂ or UV source is preferred.

Plating and Surface Preparation

PTFE’s low surface energy makes copper adhesion challenging. A sodium-naphthalene etch or plasma treatment is required before electroless copper deposition. Taconic’s ED (electrodeposited) copper foil option provides better peel strength than rolled foil on TLY-3; the datasheet specifies ≥ 6 lb/in after solder float. For immersion gold (ENIG) finishes, confirm the nickel strike adheres properly to the treated PTFE surface—a test coupon run is strongly recommended on the first lot.

Lamination and Hybrid Stackups

TLY-3 can be bonded into multilayer stackups using Taconic’s FastBond or third-party PTFE prepregs. In hybrid builds—say, TLY-3 RF layers bonded to an FR-4 digital core—CTE mismatch in the z-axis (173 ppm/°C for TLY-3 vs. ~60 ppm/°C for FR-4 below Tg) must be managed through symmetrical stackup design and controlled lamination profiles, typically 375–385 °F (190–196 °C) at 200–300 psi. The IPC-6012 qualification standard provides acceptance criteria for plated-through-hole reliability in these mixed-material builds.

Solder Assembly

TLY-3 handles standard lead-free reflow profiles (peak 245–260 °C) without delamination, provided moisture is baked out beforehand—4 hours at 120 °C is a conservative pre-bake for boards stored unsealed. Its V-0 flammability rating satisfies UL 94 requirements without additional flame-retardant additives.

Design Applications for Taconic TLY-3 PCB Substrates

GPS and GNSS Antennas

The 1.575 GHz L1 band and 1.227 GHz L2 band are classic territory for TLY-3. A Dk of 2.33 yields a patch antenna roughly 28 % wider than the same antenna on a Dk 3.5 substrate, but the resulting lower Q-factor broadens the impedance bandwidth—an advantage when covering both L1 and L2 with a single element.

Microwave Filters and Couplers

Edge-coupled and hairpin filters at C-band through Ka-band benefit from TLY-3’s low Df. At 24 GHz, insertion loss through a 5th-order microstrip filter on 10-mil TLY-3 can be 0.8–1.0 dB lower than the same topology on a Df 0.004 hydrocarbon laminate, a meaningful saving in receiver noise figure.

Phased-Array Feed Networks

Corporate feed networks for X-band and Ku-band phased arrays need tight amplitude and phase balance. TLY-3’s ±0.02 Dk tolerance across a panel keeps line-to-line phase error below 2° at 10 GHz on a 12-inch panel, assuming consistent etch factors. For larger arrays or higher frequencies, check whether FastRise 27 offers a better Dk uniformity spec for your panel size.

Satellite and Space-Qualified Hardware

PTFE’s inherent radiation tolerance and near-zero outgassing make TLY-3 a candidate for LEO and GEO satellite subsystems. Outgassing data per NASA ASTM E595 should be confirmed with Taconic for the specific lot, but PTFE-glass composites generally pass the 1.0 % TML / 0.1 % CVCM thresholds.

Cost and Lead-Time Considerations

A Taconic TLY-3 PCB is a specialty PTFE product, so expect longer lead times (typically 4–8 weeks for standard thicknesses) and higher per-panel cost compared to FR-4 or even thermoset hydrocarbon boards. Cost drivers include:

• Thickness and copper weight: Non-standard combinations (e.g., 7-mil core with 2 oz copper) may require a custom press run.
• Panel size: Taconic stocks 12 × 18 inch and 18 × 24 inch panels; odd sizes add cost.
• Surface preparation: Sodium-naphthalene or plasma treatment adds a processing step not needed for FR-4.
• Hybrid stackups: Bonding TLY-3 to dissimilar materials requires specialty prepregs and controlled lamination, increasing both cost and cycle time.

For prototyping, ordering pre-clad panels from a distributor and etching in-house or at a quick-turn shop is the fastest path. For production, lock in material allocation early—PTFE laminate supply can tighten with little warning.

Design Checklist for TLY-3 Projects

1. Confirm the operating frequency justifies PTFE cost; below 2 GHz, a lower-cost thermoset like RF-35 may suffice.
2. Specify Dk = 2.33 at your design frequency in the impedance calculator; do not use a 1 MHz value.
3. Choose ED copper for better peel strength or rolled copper for lower conductor loss at mmWave—document the choice on the fab drawing.
4. Call out sodium-naphthalene or plasma surface prep on the fabrication notes.
5. For hybrid stackups, define the bonding prepreg and its Dk/Df so the full stackup model is accurate.
6. Include a pre-bake callout (4 h / 120 °C) before reflow on the assembly drawing.
7. Add test coupons for impedance verification (IPC-2141 or IPC-TM-650 2.5.5.7) on every production panel.

Frequently Asked Questions

Is Taconic TLY-3 the same as Rogers RT/duroid 5870?

They share a Dk of 2.33 and are both PTFE-based, but TLY-3 uses woven E-glass reinforcement while RT/duroid 5870 uses random glass microfibers. TLY-3 offers better dimensional stability for CNC processing; 5870 provides slightly more isotropic Dk in the board plane. They are functional equivalents in many designs but are not drop-in replacements without re-verifying impedance and mechanical tolerances.

What is the maximum frequency for a Taconic TLY-3 PCB?

Taconic rates TLY-3 for use through at least 40 GHz. Practical limits depend on substrate thickness and conductor roughness. On 5-mil (0.127 mm) cores with rolled copper, microstrip circuits at 35–40 GHz are achievable with acceptable loss.

Can TLY-3 be used in multilayer RF boards?

Yes. TLY-3 cores can be laminated with PTFE-based bonding films into multilayer stackups, including stripline configurations. Hybrid builds combining TLY-3 with FR-4 or polyimide cores are also common, though CTE management is critical—see the fabrication section above.

How does TLY-3 compare to ceramic-filled PTFE like Rogers RO3003?

RO3003 (Dk 3.00, Df 0.0013) is ceramic-filled and offers a near-zero thermal coefficient of Dk, making it superior for narrowband designs across wide temperature ranges. TLY-3 has lower Dk and lower Df but a more negative TCDk. Choose TLY-3 when loss is the priority; choose ceramic-filled PTFE when temperature stability is.

Does TLY-3 meet IPC-4103 slash-sheet requirements?

TLY-3 aligns with IPC-4103 slash sheets for woven-glass-reinforced PTFE (e.g., /40 family). Always confirm the specific slash sheet with Taconic, as revisions and qualifications vary by thickness and copper configuration.