Built-in Self-Test Multiplexer for IC Signal Integrity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for testing receiver functions in high-speed communication systems are limited by the need for expensive external equipment and fail to provide accurate measurements of voltage and timing margins within the IC package, introducing noise and signal degradation.
Innovation Solution
A built-in self-test system with a multiplexer and control unit that generates and adjusts test signals to measure voltage and timing margins internally within the IC package, using a dummy transmitter and error detector to determine signal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external automated test equipment is used to test receiver functions, then measurement capability is provided, but measurement precision is degraded due to noise and signal degradation from external connections
Solution Approach 1:
The patent extracts the test signal generation and measurement functions from external equipment and places them inside the IC package. A dummy transmitter and error detector are integrated within the package to generate test signals and measure receiver performance internally, eliminating the need for external connections that introduce noise and signal degradation.
Solution Approach 2:
The patent introduces a dummy transmitter as an intermediary component within the IC package that generates test signals without requiring external test equipment. This intermediary enables internal measurement of receiver functions by providing a controlled test signal source that eliminates external interference.
2Measurement precision
If expensive specialized test equipment is used, then measurement capability is provided, but device complexity and cost increase
Solution Approach 1:
The patent makes the IC package self-testing by integrating both the test signal generator (dummy transmitter) and the measurement instrument (error detector) within the same package. This multi-functional approach allows the receiver to test its own performance using internal components, eliminating the need for separate expensive external test equipment.
Solution Approach 2:
The patent enables the receiver to perform self-testing by incorporating a dummy transmitter that generates test signals and an error detector that measures performance. The system tests itself internally without requiring external specialized equipment, reducing both device complexity and test equipment costs.
3Ease of operation
If loopback BIST function is used in transceivers, then functional testing is provided, but measurement capability is limited to pass/fail indication without voltage and timing margin measurements
Solution Approach 1:
The patent replaces the simple pass/fail indication mechanism with a sophisticated measurement system that uses a dummy transmitter and error detector to quantify voltage and timing margins. Instead of merely detecting errors, the system measures the actual margin values, providing precise quantitative data about receiver performance.
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
In described examples of a device (305) with built-in-self-test, a multiplexer (315) has at least first and second input terminals and is coupled to receive a first input signal (A) at the first input terminal, a second input signal (B) at the second input terminal, and selection signals (S1, S2). Also, the multiplexer (315) is coupled to output (C): the first input signal (A) in response to a first combination of the selection signals (S1, S2); the second input signal (B) in response to a second combination of the selection signals (S1, S2); and an analog summation of the first and second input signals (A, B) in response to a third combination of the selection signals (S1, S2).