Why are you pairing MMSIM141 with IC54*??? MMSIM141 is a brand new product release in 2014 while IC54* was last updated in 2011 and no update since then. It could be projected that IC54* is reaching the end of product life and phasing out. And most importantly, new product releases from Cadence are most probably not tested with IC54*, so they are NOT guaranteed to work with the old IC54*.