A Switched-Capacitor Single-ended to Differential stage for A/D conversion of IRFPA ROIC
This paper presents a Switched-Capacitor Single-ended to Differential (SC-STD) stage for A/D conversion of an Infrared Focal Plane Array (IRFPA) Readout Integration Circuit(ROIC). The SC-STD stage converts the output of the Capacitive Trans-Impedance Amplifier (CTIA) into differential signals, which can be used as the input of the subsequent A/D conversion. A novel Switched-Capacitor Common-Mode Feedback (SC-CMFB) technique with only two capacitors and single phase clock is proposed. Performances of the SC-STD stage are verified by a 14-bit column-paralleled Successive-Approximation A/D converter which is fabricated in a 0.35um CMOS-based process technology. The SFDR of the A/D converter is up to 93dB at a sampling clock of 31.25 KHz with an input signal of 1.009 KHz. The THD of the SC-STD circuit is up to -94dB at a 1V Vpp input of 1.009 KHz.