Bondwire Array Ground Wire Isolation for Inductive Coupling
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Solution Overview
Problem
Current Doherty power amplifier semiconductor package designs face challenges in miniaturization due to inductive coupling between adjacent bondwire arrays, which limits the reduction of device size, weight, and cost, especially in wireless communication systems where high power efficiency is crucial.
Innovation Solution
The introduction of ground wires on either side of bondwire arrays with the highest inductive coupling to create isolation between signal paths, reducing magnetic flux and thereby minimizing inductive coupling, allowing for a compact dual-path semiconductor package design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If discrete devices are placed close together in a semiconductor package, then device miniaturization is achieved, but inductive coupling between adjacent bondwire arrays increases causing crosstalk
Solution Approach 1:
Ground wires are introduced as intermediary elements between adjacent signal-carrying bondwire arrays. These ground wires act as mediators that provide a low-impedance return path for magnetic flux, preventing direct inductive coupling between signal wires. The ground wires are positioned in close proximity to the signal wires and connected to ground, effectively shielding the signal paths from each other while maintaining compact package dimensions.
2Object-affected harmful factors
If spatial distance between amplifiers is increased to control crosstalk, then inductive coupling is reduced, but device miniaturization is limited
Solution Approach 1:
The harmful magnetic flux and inductive coupling effects are extracted and redirected through dedicated ground wires. By separating the return current path into distinct ground wires positioned between signal arrays, the magnetic flux is channeled away from adjacent signal paths. This extraction of the harmful electromagnetic interaction allows compact placement of amplifiers without suffering from crosstalk, as the flux management function is explicitly assigned to the ground wire structure.
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 approach effectively reduces inductive coupling, enabling a high-efficiency Doherty power amplifier in a single package, suitable for devices requiring low cost, low weight, and small volume, such as base stations and mobile devices, while maintaining high power-added efficiency.
Implementation Method 1
Inductive or magnetic coupling occurs when a varying magnetic field exists between current carrying parallel conductors that are in close proximity to one another, thus inducing a voltage across the receiving conductor.
Implementation Method 2
One source of crosstalk in the semiconductor package architecture is between arrays of signal wires, referred to herein as bondwire arrays, that may be utilized between electrical devices in each of the carrier and peaking amplifiers.
Data Source
AI summary
A semiconductor package (20) includes circuits (22, 24). The circuit (22) includes electrical devices (52, 54) interconnected by a bondwire array (62). Likewise, the circuit (24) includes electrical devices (58, 60) interconnected by a bondwire array (64). Signal wires (76) of the bondwire array (62) are proximate to signal wires (78) of the bondwire array (64). Ground wires (66, 68) are located on either side of, and close to, bondwire array (62). Ground wires (70, 72) are located on either side of, and close to, bondwire array (64). The ground wires (66, 68, 70,72) are electrically coupled to a ground region (74). The ground wires (66, 68, 70, 72) reduce a magnetic flux density (140) via induced return currents (126, 130) on the ground wires of opposite polarity to signal currents (124, 128) on the bondwire arrays (62, 64) to reduce inductive coupling between the adjacent bondwire arrays (62, 64).