Multi-Level PAM Signaling for On-Package Silicon Bridge Interconnects
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Solution Overview
Problem
Conventional data communication methods across silicon bridges in integrated circuit devices face challenges with high channel loss, clock generation, cross talk, and pin-to-pin skew, which increase design complexity and power consumption, especially at higher data rates.
Innovation Solution
Implementing Pulse Amplitude Modulation (PAM-N) signaling across silicon bridges, allowing for multiple logical levels per lane to transmit more than one bit per symbol, reducing the need for micro-bumps and simplifying clocking, while using fewer micro-bumps and lower baud-rates to mitigate noise and skew issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional binary signaling is used across silicon bridges, then design complexity and power consumption increase at higher data rates, but data transmission capability is limited
Solution Approach 1:
The patent changes the signaling parameter from binary (2 levels) to multi-level PAM-N (N levels), where each symbol carries log2(N) bits. This parameter change allows higher data transmission capability without increasing the baud rate, thereby reducing the complexity of clock generation and timing synchronization while maintaining high productivity
2Speed
If higher baud rates are used to increase data rate, then data transmission speed improves, but channel loss and noise issues worsen
Solution Approach 1:
The patent changes the data rate achievement method from increasing baud rate to increasing symbols per second through multi-level modulation. By using PAM-N signaling where each symbol carries multiple bits, the system achieves high data rates at lower baud rates, thereby improving reliability by reducing the impact of channel loss and noise
3Productivity
If more micro-bumps are used to increase bandwidth, then data transmission capacity improves, but manufacturing complexity and cost increase
Solution Approach 1:
The patent merges multiple binary signaling channels into a single multi-level PAM-N channel. By combining the information carrying capacity of multiple binary channels into one multi-level channel, the system achieves the same bandwidth with fewer micro-bumps, thereby reducing manufacturing complexity and cost
4Device complexity
If conventional signaling is used, then implementation is simpler, but symbol interference and skew issues increase at high data rates
Solution Approach 1:
The patent changes the signaling parameter from binary to multi-level PAM-N, which allows achieving high data rates at lower baud rates. This parameter change reduces the duration of each symbol, thereby reducing the impact of symbol interference and skew while maintaining circuitry simplicity through standardized modulation techniques
Data Source
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AI summary
One embodiment relates to an apparatus for data communication between at least two in-package semiconductor dies (106-1, 106-2). On the first semiconductor die (106-1) in a package, a digital-to-analog converter (DAC) converts a plurality of binary signals to an analog signal. The analog signal is transmitted through a silicon bridge (108) to a second semiconductor die (106-2). Another embodiment relates to a method of data communication between at least two in-package semiconductor dies (106-1, 106-2). A plurality of binary signals is converted to an analog signal by a digital-to-analog converter on a first semiconductor die (106-1). The analog signal is transmitted through a silicon bridge (108) to a second semiconductor die (106-2). Other embodiments, aspects and features are also disclosed.