5 Replies Latest reply on Feb 24, 2013 2:49 PM by user_14586677

    Ring Oscillator

    user_14586677

      Why do neither of these oscillate ?

         

       

         

         

       

         

      Regards, Dana.

        • 1. Re: Ring Oscillator
          user_1377889

          Well, there is an optimizer which will start with thinking about what two NOTs can be replaced with...

             

           

             

          Bob

          • 2. Re: Ring Oscillator
            user_14586677

            Thanks Bob, once again I have to remember there is an extra

               

            agent in the room erasing my thoughts.

               

             

               

            Would be nice if each component had a property to "optimize or

               

            not optimize, that is the question", but then I could envision net

               

            synthesis times reaching into months.

               

             

               

            Regards, Dana.

            • 3. Re: Ring Oscillator
              user_49271930

              So Works, but questions still more...

              • 4. Re: Ring Oscillator
                user_14586677

                I did a 3 delay ring, basically got a pretty nice sinewave at 64 Mhz

                   

                on a single pin. So PSOC is a RF generator, whoda thunk .....?

                   

                Using 1 Ghz DSO for measurements. Lots of undershoot, ~ 1.2V,

                   

                but no overshoot. -030 board.

                   

                 

                   

                I plan on trying paralleling pins to see if that helps.

                   

                 

                   

                I do see a number of questions in your capture, especially no phase

                   

                difference between 2 outputs...........very low Fosc............

                   

                 

                   

                Regards, Dana.

                • 5. Re: Ring Oscillator
                  user_14586677

                  I also did a XOR doubler off ring, actually got some output

                     

                  at 124 Mhz, but only a volt pk-pk swing. Board and layout

                     

                  would have contributed to this as well.

                     

                   

                     

                  Normally on a wafer there is one or more ET test sites to help monitor

                     

                  process. And as part of that test site is a ring oscillator to keep track

                     

                  of what AC performance.

                     

                   

                     

                  Regards, Dana.