The engineer's working reference for Isola laminates & prepregs. Every part number, the real Dk / Df / Tg datasheet values, design tips, manufacturing notes, cost positioning and application matching — plus a live impedance estimator wired to each material's dielectric constant.
Search, filter by class, and sort by any spec. Tick boxes to compare materials side-by-side. Datasheet values are the typical published figures from Isola's product documentation.
| Part Number ↕ | Class ↕ | Tg °C ↕ | Td °C ↕ | Dk ↕ | Df ↕ | Cost ↕ | Datasheet |
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Df / Dk measured per Isola datasheets (typically 10 GHz for low-loss grades, 1 GHz for FR-4 grades). Cost is relative price positioning, not a quotation.
// shorter bar = better high-speed / RF performance
Every active Isola PCB grade. Click any datasheet button in the table above to open the official Isola document; the index below covers the wider catalogue including legacy and specialty grades.
Pick an Isola material and its Dk auto-loads. Enter your geometry to estimate microstrip or stripline characteristic impedance (IPC-2141 approximation) — a fast sanity-check before you commit a stack-up to your fabricator.
First-order estimate only. Final controlled impedance depends on resin content, glass style, copper roughness and your fabricator's stack-up — always confirm with their field solver.
Hard-won guidance for getting an Isola design right the first time.
FR408HR / I-Speed handle mid-speed links; step up to I-Tera MT40 for 25–56 Gbps and Tachyon 100G for 56–112 Gbps SerDes. Over-spec'ing burns budget; under-spec'ing burns your eye diagram.
At high frequency, signals "see" the glass bundles vs. resin gaps as periodic Dk variation, skewing differential pairs. Specify mechanically spread / flat glass (as on Astra MT77) or route diff-pairs at a slight angle to the weave.
Mix grades to save money: keep RF on outer Astra/I-Tera layers and run the digital core on 370HR. Pair materials with similar CTE so lamination doesn't warp or delaminate.
Prepreg is moisture- and time-sensitive — typically stored cold and dry with a limited shelf life. Stale prepreg laminates poorly. Coordinate orders with your fab's build window.
Glass-weave style and resin content shift Dk with frequency. Pull the frequency-specific Dk/Df table for your chosen grade (the estimator above starts you off) and feed it to your field solver.
At 10 GHz+, conductor loss from foil roughness can rival dielectric loss. Pair low-Df laminates like I-Tera or Tachyon with smooth (RTF / VLP) copper to actually realize the low-loss benefit.
A big reason Isola is a fab favourite: most grades drop into standard FR-4 process lines.
370HR, I-Tera MT40 and Astra MT77 share thermal behaviour that lets fabricators process them with established FR-4 drilling, plating and lamination recipes — no exotic line required, which keeps cost and yield predictable.
High-Td grades (370HR, FR408HR, IS550H) survive multiple lead-free reflow passes at 260 °C and solder-float at 288 °C without delaminating — essential for thick multilayers and rework.
370HR and FR408HR have strong track records resisting Conductive Anodic Filament growth and handle sequential lamination, making them dependable cores for dense HDI and high-layer-count boards.
Most grades offer ½, 1 and 2 oz copper in HTE, RTF (reverse-treat) and embedded-resistor foils, plus E-glass, square-weave and spread-glass fabrics — choose foil/glass to tune both loss and impedance.
Relative price tiers (not quotes). The cheapest board is the one that meets spec on the lowest-loss grade you actually need — and uses hybrid stack-ups to avoid paying premium prices for every layer.
1. Hybrid build — laminate low-loss RF skins (Astra / I-Tera) onto a cheap 370HR digital core instead of an all-premium stack. 2. Right-size the loss budget — if your channel closes on I-Speed, don't pay Tachyon prices. 3. Standard panel & glass — sticking to common thicknesses, glass styles and panel sizes avoids custom-build surcharges and improves lead time.
Start from your end application and let the matrix point you to the right Isola PCB grades.
77 GHz radar demands ultra-stable Dk and the lowest Df, with spread glass to avoid weave-induced phase error.
Base-station and mmWave front-ends need low loss at high frequency with temperature-stable performance.
High-speed digital backplanes and switch cards pushing 56–112 Gbps PAM4 channels.
High-temp, flame-retardant reliability for engine sensors, avionics and downhole electronics.
Under-hood automotive and power electronics needing low CTE and high thermal endurance.
The everyday workhorse: reliable, CAF-resistant, lead-free, fab-friendly and cost-effective.
An Isola PCB is any printed circuit board built on copper-clad laminate and prepreg from Isola Group — one of the largest base-material makers. The same board could be a $-tier 370HR multilayer or a premium Astra MT77 radar board; "Isola PCB" refers to the material platform, not a single product.
370HR is the most common high-reliability FR-4 upgrade (Tg 180 °C, lead-free, CAF-resistant). FR406 and IS410 are also widely used value grades. They run on standard FR-4 fab processes.
Both are very-low-loss. I-Tera MT40 (Df 0.0031) is a versatile RF + high-speed-digital choice with multiple Dk options; Tachyon 100G (Df 0.0021, Dk 3.02) is tuned for the longest 56–112 Gbps SerDes channels. For pure mmWave RF, step up again to Astra MT77.
Yes — virtually all modern Isola grades (370HR, 185HR, FR408HR, I-Tera, Astra, etc.) are RoHS-compliant and rated for multiple 260 °C lead-free reflow cycles.
This tool is part of PCBSync Engineering Tools. The complete Isola PCB hub — with deeper guides, stack-up libraries and fabrication support — lives at pcbsync.com/isola-pcb/.
From part-number selection to controlled impedance and hybrid stack-ups — get the full toolkit and fabrication support in one place.
Go to the Isola PCB hub ↗