This paper discusses the criteria that underlie the design of front-end sys
tems for pixel sensors of different types in a highly diversified fields of
application. In the pixel front-end systems, low level analog signals coex
ist with digital activities and the design must comply with severe limitati
ons in the area and in the power allotted to the single pixel cell. Noise a
nd radiation hardness issues are of utmost importance in several applicatio
ns. Some ways to arrive at a design which suits specific application requir
ements are discussed and the impact of the most advanced monolithic process
es is evaluated. (C) 2001 Elsevier Science B.V. All rights reserved.