Hello,
I'm trying to understand the current consumption of this part. If I am reading the datasheet correctly, it actually consumes more power with a "low" DC input signal than a 1mbps signal (4.9 and 3.2mA vs 3.2 and 2.8mA) . Why is that?
Thanks,
Stanley
Hi Stanley,
Thanks for asking your question on E2E. I'll post the relevant section of the datasheet below here to make sure we are talking about the same spec. I grabbed the specs for 5V operation, but the explanations used here will apply for other Vcc ranges as well.
ISO77xx uses an On-Off Keying based communication structure (more details can be found in the Digital Isolator Design Guide).
For example, let's discuss a device with the F suffix. When TX is HIGH, the signal through the isolation barrier is the oscillator (+ spread spectrum). This will consume a decent amount of power. When the TX signal is LOW, there is no signal through the isolation barrier - which will be the lowest power consumption. So a switching signal at 1Mbps is somewhere between these extremes.
If you have a signal that you expect to be normally LOW, it would make sense to choose a device with an "F" in the suffix of the part number as this will normally consume less current.
Best regards,
Dan
