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Keep the historical identity distinct from current supply

The reviewed 2017 ITEQ brochure identifies IT-200LK, but it does not establish current stock or every present-day construction. A complete exact-grade current technical sheet was not verified here. Do not relabel another low-loss product's numerical table as IT-200LK data.

Ask for the original approved stackup, supplier sheet and any construction changes made during previous builds. Preserve the exact laminate and prepreg forms. An alternative quotation should say explicitly that it proposes another material and identify the approval required.

Material facts and decision boundaries

Identify what the circuit is sensitive to

A long digital route, a phase-matched feed network and a resonator can respond differently to a material change. State the operating band, relevant path lengths and performance boundary. Matching one nominal impedance does not guarantee equal delay or loss.

If route length is the controlling issue, the IT-170GT budget guide supplies a separate channel-allocation task. It does not establish a substitute for IT-200LK. Any comparison needs matched geometry and suitable data for both constructions.

Use the delay model within its physical boundary

The worksheet uses a homogeneous TEM approximation: propagation delay increases with the square root of relative permittivity and with path length. Its example uses a hypothetical Dk of 4 and 100 mm path, giving approximately 667 ps one-way delay.

Microstrip does not place all its field in one uniform dielectric, so bulk Dk cannot simply replace effective permittivity. Dispersion, conductor effects and transitions are also omitted. The output is an illustration and unit check, not a circuit simulation or IT-200LK specification.

Homogeneous TEM delay illustration

Optional cost comparison from your own allowances

Use a quotation or a clearly labeled internal assumption for each input. Keep the quantity, construction and inspection scope the same when comparing alternatives. This uncalibrated planning model adds entered values; it contains no current market rates and does not issue a ³Ô¹Ïtv quotation. You can contact the team without completing it.

Recover the data used in the original solver

Record whether the old model used supplier characterization, a construction-specific design value or an extracted coupon result. Keep frequency, method, resin content, glass style and copper with that value. These details can explain a difference between an old table and a new measurement.

When comparing a more recent low-loss family such as IT-988GSE, preserve its exact suffix and construction. Do not assume that a lower chart Df automatically preserves a phase-sensitive design without geometry changes.

Separate dielectric attenuation from complete loss

Propagation and attenuation are related through the material model but answer different questions. A delay match does not establish the required insertion loss. Complete channel behavior includes copper, surface treatment, vias and launches in addition to the dielectric.

The IT-958G dielectric-loss guide explains the limited attenuation component that can be illustrated from Dk and Df. Use a complete validated model for the actual routing decision and retain the assumptions in the review package.

Request a legacy design review with a clear change boundary

Send the original IT-200LK callout, stackup, solver inputs, critical paths, frequency range, board size and quantity. Identify the required inspection and any allowed alternatives. State which performance must remain unchanged and which geometry may be revised.

The optional cost tool contains user-entered allowances only. Include re-analysis and qualification scope when comparing proposals, not just sheet price. A manufacturing response should identify the proposed construction and outstanding evidence before a material change is released.

Tie the exact grade to an electrical construction

State the channel reference planes, frequency range, routing length, copper construction, transitions and interface assumptions together. A laminate loss-tangent value is one input to that system. It is not a complete insertion-loss measurement or a guarantee that a data rate will work.

Use comparable measurement or modeling conditions when screening alternatives. Material changes can require geometry changes to preserve impedance, and copper roughness can alter the result independently of the resin system. Keep the proposed stackup and the channel analysis synchronized through fabrication review.

For procurement, identify the properties that are fixed and the alternatives that can be evaluated. Request evidence at the relevant construction and frequency rather than a broad low-loss label. Compare total delivered scope and validation effort alongside material price. A shorter or better-routed channel may change the tradeoff more than replacing a material name alone.

A useful design-data record retains both the material value and the reason it was selected. State whether the value is supplier characterization, a construction-specific design input, a measured coupon extraction or an early assumption. These sources are not interchangeable. Keep frequency, method and specimen information visible when a comparison uses more than one document.

The tool on this page starts empty because a plausible default can otherwise be mistaken for a verified grade profile. Use the example to understand the units, then replace it with project inputs. A result with many decimal places does not imply that the material or routing-loss input is known to that precision.

For a high-speed design, plan how the model will be checked. Reference planes, coupon geometry, fixtures and the acceptance boundary determine what a measurement means. A coupon that characterizes one line construction does not automatically qualify every route or transition on the board.

Keep the commercial comparison aligned with the engineering one. Quantity, copper, layer structure, test deliverables and qualification effort should be comparable. A lower material allowance can be irrelevant if the proposed construction cannot meet the channel requirement, while a premium grade may be unnecessary if the actual route already has sufficient validated margin.