- Ask a related questionWhat is a related question?A related question is a question created from another question. When the related question is created, it will be automatically linked to the original question.
We are trying to use TPS22920 load switch (and also tried TP22970 with the same results) to limit inrush current into our SFP+ module. When the module is first plugged in into a powered host board (Switch) it creates multi Amp spike. The EN pin is pulled up to the same input voltage (3.3V) that the load switch is to control. After turn on delay (about 1.5ms) we see the module actually is turning and controlling inrush current to about 300mA, which is expected.
Our capacitive load inside the SFP+ module is 84uF (ceramic caps).
It appears that the power FET transistor turns on uncontrollably during initial plug in for 50us, then turns off, and after the turn-On delay of 1.5ms it turns on second time (as expected while controlling the inrush current).
None of the data sheets scope captures show behavior when VIN transitions from low to high. The only captures shown are for VON to VOUT while VIN is already high.
Is this an expected behavior of these load switches ? Should we be looking at different hot-swappable devices ?
Jerry
