Abstract: In one aspect, an imaging device is provided which includes first and second semiconductor chips and a digital interface. The first semiconductor chip includes an active pixel sensor, a digital input/output, and a plurality of control circuits, where transistors of the active pixel sensor are all n-type or p-type transistors, and where at least one of the controls circuits operates under control of a timing signal externally input to the digital input/output. The second semiconductor chip includes a timing generator which supplies the timing signal to the digital input/output of the first semiconductor chip. The digital interface is operatively connected between the digital input/output of first semiconductor chip and the second semiconductor chip.