Signal Path Swapping Circuit for Pad-Limited ZQ Calibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor apparatuses face challenges in simultaneous ZQ calibration due to the need for two control signals and the physical constraint of crossed coupling lines between pads, which complicates wire bonding and requires a large number of pads, leading to inefficiencies in signal transmission and reception.
Innovation Solution
The semiconductor apparatus employs a configuration where semiconductor chips are rotated 180 degrees relative to each other, allowing signal paths to be swapped using a limited number of pads, enabling efficient coupling without crossed wire bondings and allowing for sequential calibration operations using a single external reference resistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two control signals are used for simultaneous ZQ calibration, then calibration functionality is improved, but device complexity and wire bonding complexity increase due to crossed coupling lines
Solution Approach 1:
The patent applies inversion by rotating one semiconductor chip 180 degrees relative to the other chip. This rotational inversion transforms the signal path connections, allowing the first pad of one chip to connect to the second pad of the other chip, and vice versa. This inverted configuration eliminates the need for crossed coupling lines and complex wire bonding arrangements that would otherwise be required for simultaneous two-sided ZQ calibration.
2Reliability
If crossed coupling lines are used between pads, then signal transmission is achieved, but manufacturing difficulty and bonding complexity increase
Solution Approach 1:
The patent introduces asymmetry in the physical arrangement of the semiconductor chips by rotating one chip 180 degrees relative to the other. This asymmetric positioning transforms the symmetric crossed coupling requirement into a non-crossed configuration. The first pad of one chip connects to the second pad of the other chip through a straightforward bonding process, eliminating the manufacturing complexity associated with creating and maintaining crossed coupling lines.
3Adaptability or versatility
If a large number of pads are used for calibration, then calibration operations are supported, but device area and complexity increase
Solution Approach 1:
The patent implements multi-functionality by enabling a single external reference resistor to serve both chips for ZQ calibration operations. The swapped pad configuration allows one chip to perform calibration while the other operates, and vice versa. This universal approach to calibration resource sharing eliminates the need for separate reference resistors and dedicated calibration pads for each chip, thereby reducing the overall device area and pad count while maintaining full calibration functionality for both chips.
Data Source
AI summary
A semiconductor circuit includes a first pad, a second pad, swapping circuit, and an internal circuit. The internal circuit receives a first external signal and a second external signal, and generates a first internal signal and a second internal signal. Based on master information and swapping information, the swapping circuit couples the internal circuit to one of first and second pads to provide a path through which the first internal signal is output and a path through which the first external signal is received, and couples the internal circuit to the other of the first and second pads to provide a path through which the second internal signal is output and a path through which the second external signal is received.