Relaxor-based ferroelectric single crystals, such as (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT, or PMNT) single crystals, exhibit large pyroelectric response, low thermal diffusivity and high temperature stability. To fabricate high performance infrared detectors with relaxor-based single crystals, the related readout circuit is investigated to increase signal-to-noise ratio, and 8×1 CMOS readout circuit is fabricated to gain very weak current.