PMC-Sierra (PMCS) was down 6.8% in early trading, as it and other communications chip makers struggled under the weight of Cisco's (CSCO) - Get Report earnings and outlook, coupled with an earnings warning from National Semiconductor (NSM) .

Vitesse Semiconductor

(VTSS)

was down 7.4%,

TriQuint Semiconductor

(TQNT)

was down 4.6% and

Applied Micro Circuits

(AMCC)

was down 4.7%.