Impedance Matching Bare-Die IC to PCB Transmission Line
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Solution Overview
Problem
Transporting millimeter-wave signals between a bare-die chip and a Printed Circuit Board (PCB) is challenging due to signal loss, impedance mismatch, and electromagnetic noise pickup, leading to complex and expensive systems.
Innovation Solution
A system that matches the impedance of a bare-die Integrated Circuit with bonding wires using a configuration of electrically conductive pads and transmission lines on the PCB, where the pads are arranged in a ground-signal-ground or side-by-side differential configuration, and the transmission lines are designed to have specific characteristics to minimize signal loss and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If discrete components such as backshort surfaces, waveguides, transmission lines and antennas are used to transport millimeter-wave signals, then signal transmission is achieved, but system complexity and cost increase
Solution Approach 1:
The patent combines multiple discrete millimeter-wave components (backshort surfaces, waveguides, transmission lines, and antennas) into an integrated substrate structure. The millimeter-wave interface is formed directly on the PCB substrate, eliminating the need for separate discrete components and reducing overall system complexity while maintaining signal transmission functionality.
Solution Approach 2:
The PCB substrate serves multiple functions simultaneously: it acts as the mounting platform for the bare-die IC, provides the millimeter-wave transmission line structure, incorporates the cavity for backshort surfaces, and integrates grounding structures. This multi-functionality reduces the number of separate components needed in the system.
2Reliability
If discrete components are used for millimeter-wave signal transport, then signal transmission is achieved, but system cost increases
Solution Approach 1:
The patent combines multiple discrete millimeter-wave components (backshort surfaces, waveguides, transmission lines, and antennas) into an integrated substrate structure. The millimeter-wave interface is formed directly on the PCB substrate, eliminating the need for separate discrete components and reducing overall system complexity while maintaining signal transmission functionality.
3Reliability
If bonding wires are used to connect bare-die contacts to PCB pads, then electrical connection is achieved, but impedance mismatch and signal loss occur
Solution Approach 1:
The patent changes the physical parameters of the transmission path by designing the bonding wires to have specific lengths and configurations that transform the impedance profile. The wires are arranged in ground-signal-ground configurations with optimized spacing and lengths to achieve impedance matching between the bare-die contacts and PCB pads, reducing reflections and signal loss.
4Reliability
If bonding wires are used to connect bare-die contacts to PCB pads, then electrical connection is achieved, but impedance mismatch occurs
Solution Approach 1:
The patent changes the physical parameters of the transmission path by designing the bonding wires to have specific lengths and configurations that transform the impedance profile. The wires are arranged in ground-signal-ground configurations with optimized spacing and lengths to achieve impedance matching between the bare-die contacts and PCB pads, reducing reflections and signal loss.
Data Source
AI summary
A system for matching impedances of a bare-die Integrated Circuit and bonding wires. A bare-die Integrated Circuit is configured to output or input, at an impedance of Z3, a millimeter-wave signal from three electrically conductive contacts. Three electrically conductive pads, printed on one of the laminas of a Printed Circuit Board (PCB) are connected to the three electrically conductive contacts via three bonding wires respectively, the bonding wires have a characteristic impedance of Z1, wherein Z1>Z3. One of the electrically conductive pads extends to form a transmission line signal trace of length L, the transmission line signal trace having a first width resulting in characteristic impedance of Z2, wherein Z2>Z3. The transmission line signal trace widens to a second width, higher than the first width, after the length of L, decreasing the characteristic impedance of the transmission line signal trace to substantially Z3 after the length L and onwards.