Reading graph-only datasheet values with AI: one IGBT test
Updated 2026-10-11
Values such as switching losses or conduction voltage often appear only in characteristic graphs, not in tables. When you ask AI for one, don't take just the number: get which figure, which curve and which conditions it was read from, with the page number.
Prompt template
Read [value name] for [part number] at [conditions: current, temperature, voltage] from its datasheet.
Give the figure number, the curve (temperature or condition) it was read from, and the page number.
If a table gives the same value, use the table value first, and mark any value read from a graph.What to check in the answer
- Figure and curve: do the curve's conditions (temperature, gate resistance, voltage) match the ones you asked for?
- Axis scale: is the axis logarithmic, and were the units (mJ or µJ, A or mA) read correctly?
- Precision: a graph value is an estimate between grid lines, so is there design margin for it?
- Table first: if a table gives the same value, was it checked against the table?
What we saw in our test
We asked for simulation thermal and loss model data for one power IGBT (Infineon IKW40N120CS6, a 16-page document). The 30 conduction-voltage, switching-loss and diode-voltage values are not in any table, only in graphs. Correct answers were worked out separately from the original datasheet graphs (September 26, 2026).
| With PartsPlan MCP | PDF attached | Web search only | |
|---|---|---|---|
| Graph values correct (within 3% or 0.05 V) of 30 | 30 / 30 | 25 / 30 | 5 / 30 |
| Average / max error | 0.3% / 3.3% | 2.0% / 6.7% | — |
| Not found | 0 | 0 | 24 (couldn't see graphs) |
| Thermal model table, 11 terms | 11 / 11 | 10 / 11 (one digit misread) | 11 / 11 |
| Same task repeated 6 times | 30 / 30 all 6 times | — | — |
This test used a single part (a 16-page document), so it does not guarantee the same accuracy on other documents or graphs. All three used the same AI model; "PDF attached" means the user found and uploaded the datasheet themselves, and that time is not included. Web search did not make up values it could not find; it left them blank.