Hi everyone. I'm trying to simulate this circuit, but I'm getting no good results. I'm using Pspice and Isis Proteus simulators. The problem is that Vout isnt 5V, in Pspice i got 11,3V and in Proteus I got 11,7V. You guys can see below a print of these simulations. Pspice - http://img515.imageshack.us/img515/63/buckpspice.jpg I got a msg on Pspice: WARNING [NET0076] Connection to unmodeled pin U1 pin 'CS', its about Pin 7 of 34063 IC. Proteus - http://img191.imageshack.us/img191/4939/buckproteus.jpg Can you guys help me? UPDATE: I realize that if i take out the Pin 7 connection, nothing changed. UPDATE2: Is Pin_7 only to read? I took out the IC and i got the same result... Something is really wrong... Can someone help me?