Nelco N4000-13 PCB: Properties, Stackups & Use

What Is the Nelco N4000-13 PCB Laminate?

Nelco N4000-13 is a glass-reinforced, modified-epoxy laminate with a dielectric constant (Dk) of approximately 3.7 and a dissipation factor (Df) of roughly 0.008, both measured at 1 GHz. Designed as a mid-performance material, the Nelco N4000-13 PCB bridges standard FR-4 and full PTFE laminates, giving designers a processable, cost-effective option for multilayer boards operating from hundreds of MHz up through C-band frequencies (4–8 GHz). Because it uses conventional epoxy-glass chemistry, N4000-13 can be drilled, plated and laminated on the same production lines as FR-4, avoiding the specialized handling that PTFE demands.

Key Electrical and Mechanical Properties

The high Tg of 210 °C and Td of 340 °C make the Nelco N4000-13 PCB compatible with lead-free assembly processes that peak at 260 °C. Its low Z-axis CTE helps preserve via reliability in boards with high layer counts, an important consideration when building 20-layer RF multilayers for phased-array or backplane applications.

Dk Drift on a Nelco N4000-13 PCB: Why It Matters

All laminates exhibit some shift in Dk across frequency, temperature and moisture. For N4000-13, Dk typically drops from roughly 3.70 at 1 GHz to about 3.60 at 10 GHz—a modest but meaningful change when your impedance budget is ±5 %. Temperature swings from −40 °C to +85 °C can add another ±0.03 to the effective Dk, and absorbed moisture pushes it upward because water has a Dk near 80.

Understanding Dk drift lets you set realistic impedance tolerances and choose the right nominal trace width. Use the estimator below to see how frequency and temperature shifts affect Dk for an epoxy-glass laminate like N4000-13. Enter the datasheet Dk at the reference frequency, then adjust the operating frequency and temperature delta.

A typical result: starting from Dk 3.70 at 1 GHz, moving to 6 GHz and adding a +50 °C temperature rise might yield an effective Dk around 3.63. On a 50 Ω microstrip designed for Dk 3.70 on 10 mil (0.254 mm) core, that shift narrows the required trace width by roughly 0.5 mil—small in absolute terms, but enough to push VSWR above 1.3 on a tightly matched filter if you ignore it. The practical response is to target the mid-band Dk in your impedance calculation and verify with a laminate thickness chart that the core you specified is in production.

Where the Nelco N4000-13 PCB Fits in the Material Spectrum

N4000-13 occupies a specific niche: better than standard FR-4 (Dk ≈ 4.3, Df ≈ 0.020) but not as low-loss as PTFE-based laminates (Dk 2.1–2.94, Df 0.001–0.003). The table below places it alongside common alternatives.

Choose N4000-13 When…

• Your operating frequency stays below roughly 6–8 GHz and insertion-loss budgets are moderate (e.g., GPS L-band, Wi-Fi 2.4/5 GHz, some S-band radar IF chains).
• You need many layers (8–20+) and want conventional FR-4-style processing without PTFE bonding films.
• Cost per panel matters: N4000-13 is typically 1.5–2× the price of commodity FR-4 but 0.3–0.5× the cost of Rogers RO4350B, making it attractive for volume production. Consult an RF laminate price guide for current comparisons.

Choose an Alternative When…

• Df 0.008 is too lossy—for Ka-band front ends or millimeter-wave modules, Nelco N9000 PTFE or ceramic-filled PTFE laminates cut loss by an order of magnitude.
• You need Dk below 3.5 for wider traces or specific impedance targets; hydrocarbon ceramic laminates like RO4350B offer Dk 3.48 with lower Df.
• Your design includes high-power amplifiers that generate significant heat; aluminum nitride or metal-core substrates handle thermal dissipation better.

Multilayer Stackup Design with N4000-13

One of N4000-13’s strongest advantages is stackup flexibility. Because the resin system is epoxy-based, it bonds well with standard FR-4 prepregs and cores, and the CTE match is close enough to avoid warpage in boards up to 20+ layers. A representative 8-layer RF/digital stackup for a Nelco N4000-13 PCB might look like this:

The thin 10 mil cores on the outer layers keep microstrip trace widths practical for 50 Ω at Dk 3.7 (roughly 17–18 mil trace for 10 mil core, depending on copper weight). The thicker 20 mil cores in the center provide mechanical stiffness and isolate digital switching noise from the RF layers. For a deeper walkthrough of layer-count trade-offs, see our guide to 8-layer RF PCB fabrication.

Fabrication Considerations for a Nelco N4000-13 PCB

Drilling and Plating

N4000-13 drills cleanly with standard carbide bits—no special diamond-coated tooling required. Recommended drill speeds and feed rates track closely with high-Tg FR-4. Hole wall quality is generally good enough for reliable electroless copper deposition followed by electrolytic plating to 1 mil (25 µm) minimum, per IPC-6012 Class 3 requirements.

Lamination

Use the supplier’s recommended lamination profile: typically a ramp to 375 °F (190 °C) at 40–50 psi, held for 60–90 minutes, then a controlled cool-down. Because the Tg is 210 °C, the cure temperature stays safely below the glass transition, preserving dimensional stability. Hybrid stackups mixing N4000-13 with PTFE layers are possible but require an intermediate bonding film (e.g., a thermoplastic adhesive sheet) and a separate lamination cycle.

Impedance Control

Fabricators should use the material-specific Dk value (3.70 at 1 GHz, or the frequency-adjusted value from the Dk drift estimator above) rather than a generic “FR-4” Dk. Many shops default to Dk 4.2 for anything on an epoxy-glass line, which would produce traces 2–3 mil too wide for a 50 Ω target—an error that shows up immediately on a TDR coupon.

Surface Finish

ENIG, immersion silver and OSP are all compatible. For wire-bondable RF modules, ENIG with 3–5 µin (0.076–0.127 µm) gold over 150 µin (3.8 µm) nickel is the standard choice. Avoid HASL on RF layers because the uneven solder coat degrades impedance uniformity along the trace.

Thermal and Reliability Performance

With a Td of 340 °C and Z-axis CTE of 45 ppm/°C below Tg, a Nelco N4000-13 PCB handles lead-free reflow profiles (peak 260 °C for 30–60 s) without delamination in properly designed stackups. Interconnect Stress Testing (IST) data from the Nelco datasheet shows survival beyond 500 thermal cycles (−55 to +125 °C) for plated through-holes with 10:1 aspect ratios, meeting JEDEC JESD22-A104 thermal cycling requirements for most commercial and industrial applications.

Moisture absorption at 0.15 % is low for an epoxy system and helps maintain stable Dk in humid environments—an advantage over some low-cost modified-epoxy alternatives that absorb 0.3 %+ and exhibit noticeable Dk drift in outdoor or automotive enclosures.

Signal Integrity: Loss Budget Example

Consider a 6-inch (152 mm) microstrip trace on 10 mil N4000-13 core at 5 GHz. Using a first-order estimate:

• Dielectric loss: α_d ≈ 27.3 × (Df / √Dk_eff) × f(GHz) ≈ 27.3 × (0.008 / √2.85) × 5 ≈ 0.65 dB/inch.
• Conductor loss (1 oz Cu, 18 mil trace): approximately 0.25 dB/inch at 5 GHz.
• Total for 6 inches: roughly 5.4 dB.

That is workable for an IF chain or a filtered signal path, but it would be excessive for a sensitive receive front-end where every tenth of a dB affects noise figure. For an LNA PCB at the same frequency, a laminate with Df ≤ 0.003 (such as RO4350B or RO3003G2) would cut the dielectric loss contribution by more than half.

Common Applications for a Nelco N4000-13 PCB

• Mixed RF/digital boards: GPS receivers, Wi-Fi access points, Bluetooth modules where the RF section operates below 6 GHz and shares a multilayer board with digital baseband.
• Backplanes and high-speed interconnects: data rates up to 10–12.5 Gbps per lane benefit from the lower Dk and Df compared to standard FR-4, improving eye-diagram margins.
• Test and instrumentation: benchtop equipment with moderate RF paths where PTFE cost is not justified.
• Prototyping for higher-frequency designs: quick-turn validation of layout and routing before committing to more expensive PTFE or ceramic laminates for production.

Frequently Asked Questions

Can Nelco N4000-13 replace FR-4 in an existing design?

Yes, if the board outline and layer count stay the same. However, because Dk drops from ~4.3 to ~3.7, trace widths for controlled impedance must be recalculated—expect 50 Ω microstrip traces to narrow by roughly 2 mil on a 10 mil core. Update your impedance model before releasing Gerbers.

Is N4000-13 suitable for 77 GHz automotive radar?

No. At millimeter-wave frequencies the Df of 0.008 produces prohibitive loss. Automotive radar front ends typically use ceramic-filled PTFE such as Rogers RO3003 series laminates with Df around 0.001.

What prepreg should be used with N4000-13 cores?

Use Nelco’s own N4000-13 prepreg to maintain Dk and CTE consistency. Mixing with standard FR-4 prepreg is possible but introduces a Dk mismatch (~4.2 vs. 3.7) that complicates impedance modeling on inner stripline layers.

How does N4000-13 compare to Isola IS680?

Both target the same mid-loss niche. IS680 offers slightly lower Df (~0.006 at 1 GHz) and a similar Dk (~3.65). The choice often comes down to regional availability and fab-shop qualification rather than electrical superiority.

Is N4000-13 still in active production?

Nelco (now part of Park Electrochemical / Nelco Products) has shifted focus, and some N4000-series grades have limited availability. Confirm lead times with your laminate distributor before committing a new design, and identify a qualified second source such as Isola IS680 or Panasonic Megtron 4.