ISO7240M: About VIORM of ISO72xx series

Masanori Tachibana

Part Number: ISO7240M

Hello support team,

I have some questions regarding "VIORM: Maximum repetitive peak isolation voltage" of ISO72xx series.
This specification is specified with AC voltage.

[Questions]
1. How much is the frequency of this AC voltage?
2. Does VIORM depend on the frequency of this AC voltage?
3. If so, is there a graph shows the relationship between the frequency of this AC voltage and VIORM?
4. The spec of VIORM is 560 Vpk for AC voltage. How much is it for DC voltage? Can I understand that it is 400 VDC for DC voltage?

Sincerely,
M. Tachibana

over 5 years ago

0 Koteshwar Rao over 5 years ago

TI__Mastermind 49445 points

Hi Tachibana-san,

Please find below my inputs.

1. The frequency of AC voltage is usually 60 Hz.

2. We do not expect VIORM spec to depend on the frequency of AC voltage. Of course this can't be said to mean all the frequencies but for most practical AC voltage frequencies, we don't expect to see any decrease in VIORM spec that is specified in datasheet.

3. Unfortunately, we do not have this data for ISO72xx family of devices. We do know from our internal testing, TI capacitive isolation performance doesn't degrade with frequency. Like I said earlier, we have only tested upto a few kHz.

4. Yes, it is safe to consider 400V as the DC working voltage spec for ISO7240M. For our latest reinforced isolators like ISO77xx family, the DC working voltage can be upto VIORM peak spec. Hence, we recommend using ISO77xx for any new designs.

Regards,
Koteshwar Rao

0 Masanori Tachibana over 5 years ago in reply to Koteshwar Rao

Genius 5350 points

Hello Rao-san,

I'm sorry for my late reply.

I understand your advice well.
It is very helpful information for me.

Sincerely,
M. Tachibana

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ISO7240M: About VIORM of ISO72xx series