Sierra Monolithics, Inc.

Alan K Tam

Binneg Y Lao

A broadband power amplifier module for high bit-rate SONET/SDH transmission channels, such as OC-192 and OC-768 applications. The power amplifier module, or also frequently referred to as modulator driver module, comprises amplifiers connected in series to amplify an input signal. A bias tee circuit is incorporated into the power amplifier module by connecting a conical shape inductor between the output stage of the amplifiers and the supply voltage and connecting a pair of blocking capacitors also at the output stage of the amplifiers. The conical shape inductor is adapted to provide high impedance over the entire bandwidth. The capacitors are adapted to provide high self-resonant frequency that is approaching or exceeding the bandwidth frequency. A power detection circuit can also be incorporated into the power amplifier module at the output stage of the amplifiers. The power detection circuit has a voltage divider circuit connected between the output stage and a ground supply. The divider circuit taps off a portion of the energy from the output stage to be measured by a detection diode. A &frac14;-wave radial matching stub is connected to the detection diode to filter RF energy. Another &frac14;-wave matching stub is connected to the divider circuit to provide grounding. Capacitors are also connected to the output of the detection diode to filter noise in the detector output voltage over a entire frequency bandwidth.

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Irvine, CA, United States of America

Alan K Tam