Question of the ISO1540 Operation with no VCC1 or VCC2

Wayne Chen (ex FAE)

Other Parts Discussed in Thread: ISO1540

Hello Sirs,

If the ISO1540 could still work correctly under the condition that VCC1 or VCC2 is zero? Could IS01540 still protect leakage current?

Thanks a lot

Wayen Chen

over 8 years ago

0 Anant Kamath over 8 years ago

TI__Intellectual 2200 points

Hi Wayen,

i am not sure if I understand your question. Are you asking what would be the leakage current on SDA/SCL pins if the corresponding supply is zero? Could you please get in touch at anantkamath@ti.com to discuss this further?

Rgds,

Anant

0 Tom Sudol over 7 years ago in reply to Anant Kamath

Prodigy 40 points

Anant,

I have the same question as this person. At least I think I do.

Question for me is, when either VCC1 or VCC2 unpowered, what is the state of SDA/SCL on the powered side? Are they tri-stated, allowing other local I2C bus activity to still occur? I looked for this info in the datasheet but did not see it.

Tom

0 Clemens Ladisch over 7 years ago in reply to Tom Sudol

Guru 281640 points

Section 6.9 specifies the VCC undervoltage lockout threshold; footnote 3 says:

Any VCC voltages, on either side, less than the minimum will ensure device lockout. Both VCC voltages greater than the maximum will prevent device lockout.

Figure 22 shows that during the lockout, the outputs are not active.

0 Tom Sudol over 7 years ago in reply to Clemens Ladisch

Prodigy 40 points

Thanks. Guess it was unclear to me what lockout meant. Perfect.

Isolation

Isolation forum

Question of the ISO1540 Operation with no VCC1 or VCC2