System and method for image detection using large area pin diode

A photo-detector circuit for barcode scanners, endoscopes, and the like, includes a large area PIN photo-diode and an amplifier. Adverse effects associated with a terminal capacitance from the large area PIN diode may be minimized by maintaining a relatively constant voltage across the input terminals of the amplifier. Noise levels may be minimized by the arrangement of the amplifier circuit and the large area PIN diode resulting in an increased signal-to-noise ratio and an increased gain-bandwidth product. Due to the large numerical aperture of the photo-detector, increased resolution and/or lower output power in a reflective imaging system may be obtained with relatively low cost components. Detection area of the large area PIN diode may be larger than approximately 25 mm2 when compared to typical PIN diodes used in photo-detector applications.