Other Parts Discussed in Thread: TCA9517A, TCA9800, ISO1640, TXS0102, TCA9406, TCA9517
My customer use our isolation IC ISO1541 at POE application to have such problems:
1. SCL is a one-way signal, and the test high and low levels meet our requirements;
2. SDA is a two-way signal, and the SDA signal from the CPU to the PSE IC is all It can meet our requirements;
3. The SDA signal from PSE IC to ISO1541 chip is good and can meet our high and low level requirements, but from ISO1541 to Level shift IC (in the direction shown by the red dotted line) this path reaches low level 800mV, as shown in the figure, and the low level required by level shift is only 150mV, so it does not meet our requirements, which indirectly causes the low level of the level shift IC to the CPU to be very high.
Would you have any suggestion to reduce the low level here to about 150mV to meet the low level requirement of the level shift IC? Thank you.