Question:
The VDE Viorm = 1250 Vpeak reinforced isolation rating for the AD7403 is much higher than the CSA reinforced rating of 415 Vrms (586 Vpeak). Why is this the case?
Answer:
Different regulatory bodies such as VDE and CSA have different criteria for rating isolation. In the case of CSA their rating is dominated by the device creepage and clearance specification, >8.3mm.
It should be noted however that the isolation rating that CSA give is based on devices with a Material Group III for a pollution degree of 2 for altitudes <2000m. This is standard practice in CSA to rate all parts to these criteria. CSA have however qualified the AD7403 package to have a CTI of ≥600 V. This means the AD7403 is qualified as a Material Group I device. Devices with a Material Group I for a pollution degree 2 for altitudes <2000m with a 8.3mm creepage and clearance specification can have a 830 Vrms reinforced working voltage. See the Safety and Regulatory Compliance Information page,
http://www.analog.com/en/interface-isolation/digital-isolators/products/quality-assurance/cu_qa_isolators_safety_certificates/resources/fca.html
for a record of all Analog Devices certification reports in relation to our iCoupler products.
