Integrated Capacitor Leadframe for Magnetic Sensor Noise Reduction
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Solution Overview
Problem
Conventional semiconductor packaging requires additional real estate on circuit boards for external components like capacitors, which increases the size of the package and complicates the assembly process, especially for magnetic sensors that need decoupling capacitors for noise reduction and electromagnetic compatibility.
Innovation Solution
Integrating capacitors directly onto the leadframe below the surface of the die, using conductive epoxy or solder to secure and electrically connect them, thereby reducing the vertical dimension of the package and minimizing the impact on the magnetic field sensitivity of magnetic sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external passive components like capacitors are used for magnetic sensors, then noise reduction and electromagnetic compatibility are improved, but the package size and circuit board real estate requirements increase
Solution Approach 1:
The patent merges the passive capacitor component with the leadframe structure by integrating the capacitor onto the leadframe substrate. The leadframe serves as both the structural support and the mounting platform for the capacitor, eliminating the need for separate external component placement. This integration maintains the noise reduction functionality while significantly reducing the overall package volume and circuit board footprint.
2Reliability
If external passive components are used for magnetic sensors, then electromagnetic compatibility is improved, but the assembly process complexity increases
Solution Approach 1:
The leadframe is designed as an integrated structure that combines the capacitor mounting function with the sensor package structure. The capacitor is mounted directly onto the leadframe during the packaging process, eliminating separate assembly steps for component placement, wiring, and mounting. This integration simplifies the assembly process while maintaining electromagnetic compatibility through proper capacitor placement and connection.
3Length of stationary object
If capacitors are integrated onto the leadframe, then package thickness is reduced, but the magnetic field sensitivity may be affected
Solution Approach 1:
The leadframe is designed with spatially differentiated zones: areas with higher magnetic permeability are positioned away from the capacitor to maintain magnetic field sensitivity, while the capacitor is placed in regions where it does not interfere with the magnetic sensing elements. This local optimization of material properties and component placement allows thin package design while preserving measurement precision.
Solution Approach 2:
The capacitor is integrated onto the leadframe in a planar configuration that utilizes the available surface area rather than increasing vertical thickness. By distributing the capacitor structure across the leadframe plane and using thin-film capacitor technologies, the package thickness is minimized while maintaining the magnetic field sensitivity through careful positioning away from the sensing elements.
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 reduces the package thickness, enhances noise reduction capabilities, and optimizes the positioning of components, allowing for more compact and efficient magnetic sensor designs with improved sensitivity and reduced eddy current effects.
Implementation Method 1
using conductive epoxy or solder to secure and electrically connect them
Data Source
Figure 1
Figure 2A~3B
Figure 4A~4D
AI summary
Methods and apparatus provide a sensor having an integrated component coupled to a leadframe. In one embodiment, a sensor includes external leads on an opposite side of a die from the integrated component. In another embodiment, a leadframe includes a slot to reduce eddy currents.