A low noise low power 512×256 ROIC for extended wavelength InGaAs FPA

Abstract

A low noise low power 512×256 readout integrated circuit (ROIC) based on Capacitance Trans-impedance Amplifier (CTIA) was designed in this paper. The ROIC with 30μm pixel-pitch and 70 fF integrated capacitance as normal structure and test structure capacitance from 5 to 60 fF, was fabricated in 0.5μm DPTM CMOS process. The results showed that output voltage was larger than 2.0V and power consumption was about 150mW, output ROIC noise was about 3.6E-4V which equivalent noise was 160e-, and the test structure noise was from 20e-to 140 e-. Compared the readout noises in Integration Then Readout (ITR) mode and Integration While Readout (IWR) mode, it indicated that in IWR mode, readout noise comes mainly from both integration capacitance and sampling capacitance, while in ITR mode, readout noise comes mostly from sampling capacitance. Finally the ROIC was flip-chip bonded with Indium bumps to extended wavelength InGaAs detectors with cutoff wavelength 2.5μm at 200K. The peak detectivity exceeded 5E11cmHz 1/2 /w with 70nA/cm 2 dark current density at 200K.