The revolutions in computer and consumer electronics technologies have given photodetector manufacturers the tools to produce devices with a very high level of integration. These advancements are a double-edged sword, however, because designers quickly take for granted the state of the art. The state of the art today becomes tomorrow's expectation, evident by the fact that the days of circuit boards populated by discreet components are quickly becoming a thing of the past. Photodetector manufacturers have three levels of integration at their disposal. The first and simplest is no integration at all.
Discreet components are the only choice.
The second level of integration is the hybrid detector, which consists of a discreet detector and a discreet signal processing chip mounted in the same package. Hybrid devices offer more flexibility and lower NRE than a monolithic photodetector. For example, manufacturers of x-ray inspection equipment all generally require a photodiode array readout by charge amplifiers. A detector manufacturer who notices this trend can develop a photodiode array coupled to discreet amplifiers to meet this requirement. Another option would be a monolithic detector including the photodiode array and signal processing circuit on a single chip.