In this paper a theoretical analysis of the R(o)A product and the detectivi
ty in a GalnAsSb infrared photovoltaic detector is reported, dependent on t
he four fundamental kinds of noise mechanism and the quantum efficiency. Th
e considerations are carried out for near room temperature and 2.5 mu m wav
elength. The analytical results show that the noise mechanisms can be reduc
ed, and correspondingly the performance of such detectors can be improved.