Fiber Optic Transceiver Module With Integrated PCB Leadframe
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Solution Overview
Problem
The existing design of Fiber Optic Transceiver (FOT) modules has limited surface area for additional component mounting, leading to degraded signal quality and reduced manufacturing yield due to long bond wires, which are difficult to manufacture and prone to breaks or cross talk.
Innovation Solution
Incorporating a printed circuit board (PCB) attached to the leadframe, allowing for increased surface area, shorter bond wires, and improved thermal alignment, enabling additional component integration and enhanced signal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a standard four-pin leadframe is used without PCB, then the structure is simple and manufacturing is easier, but the surface area for component mounting is limited and signal quality is degraded
Solution Approach 1:
The patent merges the leadframe and PCB into a single integrated structure where the PCB is attached to the leadframe, combining the electrical connection function of the leadframe with the component mounting function of the PCB, thereby increasing the available surface area for components without significantly increasing overall complexity
Solution Approach 2:
The patent transitions from a two-dimensional leadframe surface to a three-dimensional structure by attaching a PCB vertically to the leadframe, effectively adding another dimension for component placement and dramatically increasing the available mounting area
2Ease of operation
If long bond wires are used to connect components to the leadframe, then the reachability to distant components is improved, but manufacturing yield is reduced due to breaks and cross talk
Solution Approach 1:
The PCB acts as an intermediary between the components and the leadframe, providing intermediate connection points (bond pads) that are much closer to the components. This eliminates the need for long bond wires by introducing the PCB as a mediator with multiple short connection points
Solution Approach 2:
The patent segments the single long bond wire connection into multiple short connections: components connect to bond pads on the PCB, and the PCB connects to the leadframe via shorter bond wires or solder joints, thereby reducing the length and improving reliability of each individual connection
3Area of stationary object
If additional components are mounted on external motherboard, then the FOT module surface area constraint is avoided, but signal quality is degraded
Solution Approach 1:
The patent merges the FOT module with the PCB to create an integrated assembly, eliminating the need for external motherboard mounting. This integration maintains signal quality by keeping all components within a single packaged unit with controlled signal paths, while providing ample mounting area on the PCB
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances signal quality, increases manufacturing yield, and improves reliability over temperature changes by providing additional surface area for components and reducing bond wire length, while maintaining alignment of optical elements.
Implementation Method 1
placing an electrically conductive adhesive material on an FOT leadframe... placing the PCB in contact with the leadframe such that one or more of the electrically conductive bond pads of the PCB comes into contact with the electrically conductive adhesive material
Implementation Method 2
The first ends of at least some of the bond wires are attached to electrical contact pads on the IC and the second ends of at least some of the bond wires are attached to at least some of the electrically conductive bond pads on the PCB
Implementation Method 3
The encapsulation has at least a first optical element formed therein at a location on the encapsulation for coupling light between the first optical active device and a first end of an optical fiber
Implementation Method 4
The photodiode converts the optical data signal into an electrical data signal
Implementation Method 5
The electrical drive current signal is applied to a light source, such as, for example, a light emitting diode (LED), which causes it to emit an optical data signal
Data Source
AI summary
A fiber optic transceiver (FOT) module is provided that has a circuit board attached to the FOT leadframe. The circuit board, which is typically a printed circuit board (PCB), provides several advantages over typical FOT module designs in that it provides additional surface area for mounting additional components, enables components to be moved from the motherboard into the module, allows the I/O pin count of the FOT module to be increased without increasing the width or footprint associated with the module, allows bond wires to be shortened, provides improved performance over changes in temperature, allows manufacturing yield to be improved, and enables improvements in signal integrity to be realized.