We designed a new type of infrared focal plane readout circuit with combined pixels to meet the development requirements of both high sensitivity and high dynamic range. The designed circuit can be used for shortwave infrared focal plane detector arrays. Traditional pixels typically use only one inputstage ,which makes itdifficultto balance high sensitivity and high dynamic range. In contrast ,combined pixels use a capacitive trans-impedance amplifier (CTIA) input stage along with a high dynamic range input stage ,thereby inheriting their advantages. The specific layoutof a combined pixel contains one high-dynamic-range input stage located in the middle of every 2× 2 CTIA high-sensitivity input stage. This high dynamic range input stage can be switched between direct injection and logarithmic modes. We realized the layout ofa320× 256 readoutcircuitforcombined pixelarrayswith a 15μm pitch using a0. 18μm 3. 3 V standard CMOS process . Simulation results show that both high sensitivity and a high dynamic range can be achieved using small integral capacitors and a high dynamic range in combination with the logarithmic mode.