Goldman Sachs downgraded PMC-Sierra (PMCS

), Vitesse Semiconductor (VTSS

) and Applied Micro Circuits (AMCC

) to market outperform from trading buy.

Analyst Nathaniel Cohn says while there's no change to his view that these can be very interesting trading stocks given volatility, he believes that high valuations, limited visibility on sustainable recovery, and a lack of near-term catalysts beyond SuperComm will likely cause trading ranges to trend lower in near-term. As a result of what he thinks remain challenging end-market conditions, Cohn cut estimates:

PMC-Sierra: $0.10 2001 EPS estimate to $0.06, and $0.45 2002 to $0.37; Vitesse: $0.42 fiscal 2001 (Sept.) EPS to $0.40, and $0.32 2002 to $0.27; Applied Micro: $0.10 fiscal 2002 (March) EPS to $0.05, and $0.31 fiscal 2003 to $0.25.