DIFFERENTIAL TRANSIMPEDANCE AMPLIFIER FOR OPTICAL RECEIVER APPLICATIONS

摘要

PURPOSE: A differential trans impedance amplifier for a photo diode is provided, which reduce an area of a preamplifier and has a high speed, a high gain, a low noise and wide band characteristics. CONSTITUTION: The first buffer(10) of control cascode structure insulates a photo diode by receiving an output of the photo diode converting an optical pulse signal into a photovoltaic force. The second buffer(20) is formed symmetrically to the first buffer for symmetry of a differential structure. A differential amplifier(30) receives the outputs of the first buffer and the second buffer. A threshold voltage compensation load stage(40) is intervened between the differential amplifier and a power supply to widen a dynamic range with a wide swing width. The third buffer(50) of cascode structure obtains DC level shifting and low power consumption by receiving a differential output value of the differential amplifier. And an output stage(60) enables a high speed operation by widening a bandwidth of a device with a shunt peaking technology as to the output of the third buffer.