IC Package Switch Circuit for Die Testing
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Solution Overview
Problem
Integrated circuit packages with multiple dies face challenges in testing due to the lack of externally accessible input and output pin connectors, making it difficult to test the internal connections between the dies.
Innovation Solution
An integrated circuit package design with a switch circuit that allows for the selective coupling of input and output terminals of the dies to external terminals, enabling direct access for testing without the need for additional external connectors beyond control terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the dies are interconnected internally in the package with bond wires, then the number of external pin connectors is minimised, but the ability to test the internal connections and terminals is lost
Solution Approach 1:
A switch circuit is introduced as an intermediary component between the external pin connectors and the internal die terminals. This switch circuit includes multiple switches that can selectively connect different internal terminals to external pins, enabling both normal operation and testing modes without requiring additional external connectors.
Solution Approach 2:
The package structure transitions from a static configuration to a dynamic one where the switch circuit can change connection states. During normal operation, the switches configure connections for standard die-to-die communication. During testing, the switches reconfigure to provide external access to internal terminals that would otherwise be inaccessible.
2Difficulty of detecting and measuring
If additional external terminals are added for testing, then the testing capability is improved, but the minimisation of pin count is compromised
Solution Approach 1:
The existing external pin connectors are designed to serve multiple functions: they act as input/output terminals during normal operation and as test access points during testing. The switch circuit enables the same physical pins to be dynamically reassigned for different purposes, eliminating the need for dedicated test pins.
Solution Approach 2:
The package uses its own existing external pin connectors and internal switch circuitry to provide testing capability, rather than requiring separate dedicated test interfaces. The system essentially tests itself by reconfiguring its existing resources.
Data Source
AI summary
An integrated circuit package (1) comprising first and second dies on a laminate (5) in a resin encapsulating housing (6) comprises a digital signal processing integrated circuit (8) fabricated on the first die (2), and a digital-to-analogue converting circuit (9) fabricated on the second die (3). First external terminals (16) are selectively coupled to corresponding first input terminals (10) of the digital signal processing circuit (8) through corresponding primary input switches (19), and first output terminals (11) of the digital signal processing circuit (8) are selectively coupled through primary output switches (23) and secondary input switches (25) to second input terminals (12) of the digital-to-analogue converting circuit (9). Second output terminals (13) of the digital-to-analogue converting circuit (9) are selectively coupled to second external terminals (17) through secondary output switches (30). The switches (19,23,25,30) are configurable for selectively testing functions of the digital signal processing circuit (8) and the digital-to-analogue converting circuit (9) between selectable combinations of first input and output terminals (10,11) and second input and output terminals (12,13) by applying a test signal to an appropriate one of the first external terminals (16), and reading a response signal on an appropriate second external terminal (17).