ISO1540: VOL1 issue

Derek Liu

Part Number: ISO1540

Found the VOL1 of ISO1540 is ~0.88V, but the I2C's VIL spec of device is 0.8V, seem like it is out of the device's spec. wondering if there are any ideas how to fix it? Thank you.

Derek

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 317370 points

It should be below 0.8 V when the pull-up current is at most 3.5 mA. What pull-up resistors are you using?

0 Derek Liu over 1 year ago

Prodigy 10 points

Pull-up resistors is 1K ohm.

0 Derek Liu over 1 year ago in reply to Clemens Ladisch

Prodigy 10 points

i tried to use 560 and 10K ohm instead of 1K ohm, the VIL is the same as 1K ohm case. wondering if there are any ideas?

0 Clemens Ladisch over 1 year ago in reply to Derek Liu

Guru 317370 points

This is beyond the V_OL1 specification in the datasheet. Are you sure that this is your only pull-up resistor? (Does the voltage rise if you leave it out?)

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ISO1540: VOL1 issue