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Distinguish GT from GRA2

The current ITEQ introduction lists IT-170GT separately, with headline Dk 3.90 and Df 0.0095 on the chart's 50% resin-content basis. Keep the exact sheet, frequency and method with any design value. A chart entry cannot describe every available dielectric construction.

For a matched cost-versus-loss comparison, visit IT-170GRA2. Do not treat the two names as interchangeable or assume the digits imply a common resin and reinforcement. The proposed stackup needs its own electrical model.

Material facts and decision boundaries

Define the loss boundary at a named frequency

Start with the interface's actual reference planes and allowable loss. Identify which package, connector and via effects are included. An allocation measured between board launches cannot be mixed casually with one that includes packages or test fixtures.

Reserve the chosen engineering margin explicitly. A positive remainder means only that the entered allocations leave arithmetic room for routing. Return loss, crosstalk, skew and other interface criteria may still govern the design independently of insertion loss.

Routing length from remaining loss allocation

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 吃瓜tv quotation. You can contact the team without completing it.

Convert the remainder into a conditional route length

The worksheet subtracts fixed losses and margin from the total budget, then divides by an entered complete routing-loss rate. In the hypothetical example, 20 dB minus 5 dB fixed loss and 3 dB margin leaves 12 dB. At 1 dB/in, that corresponds to 12 inches.

The result is conditional on the rate and boundary. It is not a maximum IT-170GT length or an approved bitrate. If a route includes different constructions, model their segments appropriately rather than assigning the best segment's rate to the entire path.

Include copper and geometry in the rate

Use a validated line model or suitable measurement for the proposed copper, dielectric and trace shape. Df accounts for dielectric behavior; complete attenuation also includes conductor effects and the actual electromagnetic field distribution.

The IT-180I review emphasizes the difference between identity evidence and electrical data. A safety document can identify a supplied material but does not furnish a reliable dB/in input. Do not estimate complete attenuation from a product-family name.

Revisit legacy routes without inventing compatibility

An existing IT-200LK drawing may need a new source or construction review. Preserve its electrical requirements and compare an IT-170GT proposal against them. Similar loss-category labels do not establish a drop-in replacement.

Check whether connectors, routing length, copper and acceptance criteria have changed since the old design. A replacement may need different trace dimensions or additional verification. Keep that work visible in both the engineering decision and commercial scope.

Request a quote around the critical channel

Send the exact material request, layer structure, copper, route lengths, frequency boundary and required testing with board dimensions and quantity. Identify which inputs are fixed and which can be adjusted. A short list of critical channels is more actionable than a broad high-speed label.

The optional cost model adds user-entered allowances only. Compare proposals on the same construction and evidence scope, and attach the local worksheet manually if useful. The final manufacturing proposal still requires review of the actual design and material supply.

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.