# Datasheet-accuracy audit checklist

A characterization page **is** a datasheet. Every value and every chart must trace
to a specific datasheet figure/table. **Cite the page number for every finding.**

## Procedure
1. Extract the page's claims to plain text (strip HTML tags).
2. Get the datasheet: `pdftotext -layout DS.pdf -` for the tables; render figures
   with `pdftoppm -png -r 300 -f <pg> -l <pg>` and, for a specific curve, crop with
   `-x -y -W -H` at high DPI then Read the PNG. (ImageMagick is NOT installed.)
3. For the target part specifically (a series datasheet covers many variants — pick
   the right row: colour/value/voltage), compare EACH value and EACH chart curve.

## Value checklist (per component type)
- **LED:** Vf typ/max, λD (dominant), λP (peak), IV (mcd) @ test current, IF max,
  IFP (pulse note), VR, Pd, viewing angle 2θ½, material (AlInGaP/InGaN), lens,
  operating/storage temp. Package L×W×H + tolerance. Solder pattern (pad W, H, gap).
- **MLCC / cap:** capacitance, tolerance, rated voltage, dielectric, package L×W×T
  + termination band, dissipation factor, insulation resistance, temp range, reflow.
- **Resistor:** value, tolerance, power rating, TCR, package, derating curve.

## Charts — verify the CURVE, not just the caption
An SVG `<path>` can plot the wrong numbers even with a corrected caption. For each
chart: read the datasheet curve at several points, convert to the chart's pixel
coords (`x = x0 + (v-v0)*scale`, `y = y0 - value*scale`), and redraw the path.

## Common discrepancies found in the wild
- **Land pattern "center-to-center" that is actually the edge-to-edge GAP.** The
  datasheet solder-pattern dimension between two pads is usually the gap. c-c =
  pad_width + gap. (Seen on IN-S42ATR: page said c-c 0.6mm; Fig 1's 0.6 is the gap,
  real c-c = 0.4 + 0.6 = 1.0mm.)
- **Brightness-vs-current / vs-temperature curves drawn to invented numbers**
  (e.g. "+55% at 40mA" when the datasheet curve reads +70%; "−30% at 70°C" when it's
  ~−40%). Redraw from the datasheet curve.
- **FWHM / spectral width stated as a value** when the datasheet's Δλ column is blank
  for that colour — remove it (it's a guess, not a spec).
- **Footprint pad size not matching the datasheet solder pattern** (e.g. width/height
  swapped: 0.6×0.5 where Fig 1 says 0.4×0.6). Fix the `.kicad_mod` AND regenerate the
  fpview + ct footprint SVG + the composite pads.
- **3D model height = the generic KiCad body** (0402 LED_0402 is 0.5mm) vs the
  datasheet (0.45mm). Scale the STEP + composite to the datasheet height.
- **Derating curve values that look wrong but are actually right** — verify against
  the datasheet's own curve before "fixing". (IN-S42ATR: the derating curve peaks at
  30mA even though the abs-max table says 25mA — the datasheet is internally
  inconsistent; the page correctly reproduced the curve.)