In this work, we have exploited the possibility of swapping the functionali
ties of the two stages of fast frontend electronics based on the usual prea
mplifier and shaper structure. Measurements on a prototype of the CMS front
end chip (APV6) confirm what expected from general considerations: invarian
ce of the output shape and amplitude, and tolerance to very high particle r
ates. The noise may increase marginally because of the different impedance
of the first stage, which depends on the peaking time. (C) 2001 Elsevier Sc
ience B.V. All rights reserved.