Design and implementation of infrared readout circuit using a new input circuit of current mirroring direct injection (CMDI)

A new readout structure for infrared (IR) focal plane arrays (FPA) is presented in this paper. By applying a new input circuit of current mirroring direct injection (CMDI), we realised a high-performance readout circuit for IRFPA. It was found from the SPICE simulation that the CMDI inherently makes the detector bias stable as well as has almost 100% injection efficiency to the readout circuit from the detector even for low RDA values because it has almost zero input impedance. Compared with previous other input circuits, it has also many advantages such as small area and low power consumption. A readout chip including the CMDI inputt circuit has been designed and fabricated for MWIR 1x128 staggered linear HgCdTe infrared detector arrays using 1.2 um single-poly-double-metal N-well CMOS technology. From the measurement results of the fabricated chip, the readout function was successfully verified at 77 K with 5 V supply voltage.