Trans-impedance amplifier for high speed optical-electrical interfaces

摘要

The differential trans-impedance amplifier uses trans-resistance(s) connected between the input nodes of a first differential amplifier, to implement a trans-impedance differential amplifier in a differential fashion and has two identical resistances, each connected between the photodiode and a respective DC voltage rail of a common bias network of the photodiode adapted to reverse bias the photodiode. The biasing resistances may be much larger than the trans-resistance(s) to prevent drawing any significant signal current from the photodiode. The amplifier may retain the advantages of a classical differential topology while effectively overcoming drawbacks that arise in high data rate applications.

主权项

1. A differential trans-impedance amplifier circuit comprising:
an amplifier having a pair of input nodes and configured to generate an amplified replica of a differential voltage on said pair of input nodes; a photodiode; a pair of DC-blocking capacitors coupling said photodiode to said pair of input nodes; at least one trans-resistance coupled between said pair of input nodes of said amplifier; and a bias network comprising two identical photodiode biasing resistances each greater than said at least one trans-resistance each photodiode biasing resistance coupled in series between said photodiode and a respective DC voltage.