Sumitomo Electric Industries, Limited

Yasuki Mikamura

Toshio Mizue

Ichiro Tonai

An electronic circuit is formed on a wiring substrate capable of cross wiring, and an electrode of the wiring substrate and a connecting portion of a lead frame are electrically connected to each other without wire bonding. As a consequence, while the substrate size is enhanced, the wiring pitch is reduced, whereby the electronic circuit can have a larger area and a larger scale. Further, the difference between the thickness of the encapsulating resin on the upper surface of the lead frame from the upper surface of the wiring substrate and the thickness of the encapsulating resin on the lower surface of the lead frame is made smaller than the thickness of the wiring substrate, whereby the occurring stress is reduced, and the encapsulating resin is kept from being distorted or cracking. Here realized is an optical module having a configuration in which, while the electronic circuit has a larger scale, the stability and durability are maintained.

Optical module

A phase-inverting amplifier includes an input-stage FET, a load thereof and a gain control circuit. The gain control circuit is provided in parallel with the load, and reduces an effective load resistance to lower an open-loop gain of the phase-inverting amplifier when a current flowing through the load exceeds a predetermined value. The gain control circuit is typically a FET whose gate is biased at a constant voltage. A feedback resistor is provided in a negative feedback path of the phase-inverting amplifier. A bypass circuit is provided in parallel with the feedback resistor, and reduces an effective feedback resistance when a feedback quantity exceeds a predetermined value.

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Kanagawa, Japan

Yasuki Mikamura