OSI Optoelectronics Tetra-Lateral Positions Sensing Detector SC-4D

Tetra-lateral position sensing detectors are manufactured with one single resistive layer for both one and two dimensional measurements. They feature a common anode and two cathodes for one dimensional position sensing or four cathodes for two dimensional position sensing. These detectors are best when used in applications that require measurement over a wide spatial range. They offer high response uniformity, low dark current, and good position linearity over 64% of the sensing area. A reverse bias should be applied to these detectors to achieve optimum current linearity when large light signals are present. The circuit on the opposite page represents a typical circuit set up for two dimensional tetra-lateral PSDs. For further details as well as the set up for one dimensional PSDs refer t the "Photodiode Characteristics" section of the catalog. Note that the maximum recommended incident power density is 10 mW / cm2. Furthermore, typical uniformity of response for a 1 mm ? spot size is ± 5% for SC-25D and SC-50D and ± 2% for all other tetra-lateral devices.