The spec for the HCPL3700M (AC voltage detection IC) lists an "External Clearance" of ≥7.4mm.
Is this saying that no component or exposed trace should be within 7.4mm on any side of the chip? Or is it just stating the clearance spec that its own footprint is meeting? (I note that the AC pins are 7.62mm from each other and from the low voltage pins on the other side of the IC, which seems suspiciously close to 7.4mm.)
If it's specifying clearance to other components, then as far as I understand this would contradict most recommendations for clearances of high voltage conductors on circuit boards. E.g. 240VAC comes to ~2.5mm, depending on the standard. Creepage specs are naturally a bit higher, but still well under 7.4mm. And after all, the HCPL3700M's own AC input pins have slightly less than 2.54mm clearance from their neighboring (post-internal-rectifier) pins.
To get the 2.5mm figure I used the Saturn calculator for an external, uncoated trace, 340V peak, under 3050m, IPC-2221B. In my current board layout, the nearest metal is ~3mm. Would this be safe?
Relevant section from the PDF: