Hi, all Does anybody know LTspice well ? I am having difficulty simulating. The following is what I did in order to simulate it. If I did something wrong, please let me know. I am at a point that I don't know where to start, so I am posting this message. I have done everything that is available to create a spice model for MIC4422. However, some reason it did not work at all. So, I am going to type the procedure that I went through step by step. If anyone recognize what I did wrong, please correct me. I do appreciate it. 1) I downloaded MIC4422, from http://www.micrel.com/_Models1/SPICE/ISPICE/MIC4422ISMOD.txt 2) I renamed this file to MIC4422.lib, MIC4422.sub, MIC4422.txt 3) I opened the LTspice, and edited the symbol that is already existed. (In LTspice, component-> Misc-> DIP8) 4) After I edited DIP8 file (this symbol has 8 pins, so I deleted 4 pins accordingly because MIC4422.txt shows only 4 pins used), I saved as MIC4422 in Misc directory. 5) I closed LTspice. 6) I copied the MIC4422.lib, MIC4422.sub, and MIC4422.txt files into C\program files\LTC\LTspiceIV\lib\sub 7) I re-opened the LTspice and built the rest of circuit. In the meantime, spice directive, I typed .INCLUDE MIC4422.lib, .MODEL MIC4422, .SUBCKT, .INCLUDE MIC4422, .INCLUDE MIC4422.SUB 8) After all of these, I simulated and got a message saying, "could not open include file "MIC442". so now, what is the problem ? I believe I followed everything correctly, but some reason my simulation is not working at all. Can someone please explain what I did or what I need to fix or any type of help ? Thank you very much in advance.