Part Number: ISOW7821
Customer is require high isolation voltage condition below;
・Isolation voltage: 5500Vac / 1min
※DC/DC: 5Vin ⇒ 5Vout / 10mA
Please let me know about three points below for ISOW7821.
①ISOW7821 is 1414Vdc, but isolation voltage is 5000Vac / 1min.
I think that cascade two ISOW7821 became to increase isolation voltage, is it correct?
I want to know any idea for ISOWxxxx series match 5500Vac / 1min.
②Is there specification graph for Isolation capacitor Life time? (Graph of Time of fail vs Stress voltage)
③Is there test data for Failure mode?
（I want to know these test data based on Vac or Vdc）
Thanks for using our E2E forums.
1). Technically, yes - one can cascade isolators to achieve higher isolation voltage ratings. However, before we consider that option, there might be better solutions available based on end equipment needs. For example, one can use the ISO7821 (no W in the part name; only data isolator without power), which can support 2121V (DC) and 5700V rms (1 minute) in the same footprint (16DW). You can then use an SN6505 part to drive a transformer to get isolated power. The 10mA load current budget at 5V should be easily handled since the 6505 can provide up to 1A of current.
Can you please share more details on the end equipment that needs this high isolation voltage Vac spec?
2) We will follow-up with you on this. The ISO7821 (no "W") part linked above contains the capacitor lifetime data in the datasheet, but this is for data path only. We will try to see if we can provide a similar curve for the W parts also [data + power].
3) This data unfortunately cannot be shared on a public forum. Sharing this will require an NDA and we will have to pursue this offline over PM/email. Is this something you wish to pursue? If yes, can we please reach out to you/your end customer over email to route this through the correct channels?
We are glad that we were able to resolve this issue, and will now proceed to close this thread.
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