RTC Terminal Layout to Withstand Solder Crack Coupling Failures
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Solution Overview
Problem
Real-time clock devices face functional failures due to solder cracks caused by stress, leading to coupling failures at external terminals, which can render them unable to perform required functions.
Innovation Solution
A real-time clock device configuration with a resonator, oscillation circuit, clocking circuit, functional circuit, and package with strategically arranged external terminals, including a switching circuit that controls the coupling of functional signal terminals, preventing immediate power-on signals and reducing the likelihood of coupling failures by arranging functional signal terminals outside clocking and power supply terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If external terminals are provided in the package for signal input/output, then the real-time clock device can perform required functions, but solder cracks may occur due to stress acting on the solder, leading to coupling failures
Solution Approach 1:
The patent segments the external terminals into different groups based on their susceptibility to stress and importance for device functionality. Critical terminals for basic clocking functions are separated from terminals for optional functional features, allowing the device to maintain essential operations even when non-critical terminals experience solder failures
Solution Approach 2:
The patent applies preliminary action by strategically positioning critical clocking terminals in locations less susceptible to solder stress before the device is subjected to thermal or mechanical stress. The terminal arrangement is predetermined to place high-potential power supply, low-potential power supply, and clocking signal terminals in more reliable positions, preventing future coupling failures
2Ease of operation
If functional signal terminals are arranged in the package, then the functional circuit can be controlled, but they are more susceptible to solder cracks when arranged outside other terminals
Solution Approach 1:
The patent applies local quality by assigning different arrangement priorities to different terminal types based on their functional importance. Critical terminals (power supply and clocking) are placed in locations with higher reliability, while functional signal terminals that are less critical are placed outside, creating localized quality differences in terminal susceptibility to stress
3Area of stationary object
If all external terminals are arranged in a compact package, then the device size is reduced, but stress concentration increases leading to higher crack risk
Solution Approach 1:
The patent uses preliminary action to pre-identify and position stress-vulnerable terminals in locations that minimize stress concentration within the compact package layout. By predetermined arrangement of power supply and clocking terminals in more protected positions, the design proactively prevents stress-related failures before they occur
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 configuration enhances the reliability of real-time clock devices by minimizing the impact of solder cracks on clocking circuit functionality, ensuring the device can maintain basic functions even under stress conditions.
Implementation Method 1
a resonator; an oscillation circuit that oscillates the resonator
Data Source
AI summary
A real-time clock device includes a package that houses a resonator, an oscillation circuit, a clocking circuit, and a functional circuit, and on which external terminals are formed. The external terminals include a high-potential power supply terminal coupled to a high-potential power supply, a low-potential power supply terminal coupled to a low-potential power supply, a clocking signal terminal used at least for controlling the clocking circuit, and a functional signal terminal used for controlling the functional circuit, the functional signal terminal is arranged outside the high-potential power supply terminal, the low-potential power supply terminal, and the clocking signal terminal in a direction in which the external terminals are arranged, and the real-time clock device further includes a switching circuit that switches between a state in which the functional signal terminal and the functional circuit are coupled and a state in which the functional signal terminal and the functional circuit are not coupled.