| 摘要 |
An improved transimpedance amplifier having a wide bandwidth, stable operation and high gain including a cascode input transistor stage. The cascode input stage includes a JFET transistor coupled to a photodiode output providing the current input for the transimpedance amplifier. The output of the JFET transistor is coupled to the emitter of a bipolar transistor having its base grounded. The JFET reduces current noise in the transimpedance amplifier and the bipolar transistor provides the required high gain while coupling the Miller capacitance to ground. The output of the bipolar transistor is coupled through the base of a second bipolar transistor which provides a buffer for the transimpedance amplifier. An output level shift provides the feedback voltage to the cascode input stage.
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