| 摘要 |
PURPOSE:To provide no restrictions to a pre-amplifier connected to the output side, a receiver, a controller, and the like by a method wherein a photo diode and an amplifier of low output impedance which amplifies the output of this photo diode are formed on a single semiconductor chip. CONSTITUTION:A buffer amplifier 4 is added to a pin photo diode 1, which are formed on a single semiconductor chip. This buffer amplifier 4 sets the output impedance low. For example, setting at emitter follower output not only causes a low output impedance, but also allows the buffer amplifier 4 to have amplification, and enables the omission of a receiving pre-amplifier in the latter case. Since the output impedance is low, the input impedance of the pre-amplifier 2 and the like receiving the output of the buffer amplifier 4 is not restricted to high impedance; accordingly, the range of applications enlarges. |
