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Synopsys Introduces Industry¡¯s First 40G UCIe IP Solution to Power High-Performance Multi-Die Designs

Manuel Mota

Sep 09, 2024 / 4 min read

With physical limitations slowing Moore¡¯s law and AI pushing the limits of technology, compute requirements and the demand for more processing power have grown exponentially. Modern data centers now require multi-die designs to power generative AI applications, driving many technology requirements including high-bandwidth and low-power die-to-die connectivity.

To ensure multi-die design success, the Universal Chiplet Interconnect Express (UCIe) specification streamlines die-to-die connectivity in multi-die designs by prioritizing interoperability, keeping latency down, enabling disparate dies to communicate with each other, and more.

Synopsys continues to stand at the forefront of the UCIe evolution. From teaming up with Intel on the world¡¯s first successful UCIe interoperability test chip demonstration to with controller, PHY, and verification IP, Synopsys has empowered technology visionaries with a comprehensive and scalable multi-die solution from early architecture exploration to manufacturing.

Now, Synopsys is building on its mature and heavily adopted UCIe IP solution to address customer needs for maximum bandwidth and energy efficiency with the 40G UCIe IP.

40g ucie ip data center ai chips

New 40G UCIe IP Solution

Synopsys¡¯ new 40G UCIe IP solution supports 25% more bandwidth compared to the UCIe specification, allowing 12.9Tbps/mm of data to travel between heterogeneous and homogeneous dies without impacting energy efficiency and silicon footprint.

In addition to complying with the latest UCIe 2.0 specification, while going beyond the standard with additional bandwidth efficiency, the new 40G UCIe IP solution:

  • Allows companies to experience the best of both worlds. In a use case like a large AI training device where the die is split into smaller dies, high bandwidth is required to enable seamless data movement between dies. In edge AI or a mobile device, dies performing distinct functions may be attached in a more complex system with limited data required to travel between them, making interoperability more critical.
  • Meets the needs of demanding applications like AI training SoCs, high-performance server chips, ADAS SoCs, custom HBM stacks using UCIe, and more while enabling the use of low-cost substrate packaging for high performance multi-die packages.

The new 40G UCIe IP is built on the current, mature architecture, which has achieved interoperability and silicon successes across multiple advanced foundries and processes. Customers benefit from accelerated interoperability, reduced area for maximum bandwidth, flexibility while delivering faster speeds, design support for any packaging type, and, finally, improved visibility, reliability, and system testing.

The IP solution, including PHY, controller, and verification IP, features a complete protocol stack. The physical layer with a controller on top supports a seamless connection between two dies via one of the multiple protocols supported, including AXI, CHI C2C, CXS, PCIe, CXL, and streaming, to allow a die-to-die connection between fabrics.

Differentiated Capabilities

Synopsys¡¯ new 40G UCIe IP solution offers features that make it easy to integrate and simplify the customer use cycle, including:

  • A single reference clock that supports 100 MHz reference clocking for all UCIe PHYs and eliminates the need for additional high-frequency system PLLs. The internal PLL generates all the high-speed peripheral clock (pclk) and lower local clock (lclk) frequencies needed during initialization and regular operation. The lclk is shared with the controller to further simplify system integration.
  • Embedded mission mode signal integrity monitors (SIMs) that are integrated into the IP for diagnosis and analysis from in-design to in-field, ensuring multi-die package reliability and quality. The comprehensive test features embedded in the PHY allow high-coverage testing of the PHY at the wafer level (for Known Good Die) and after package assembly (including die-to-die interconnect).
  • Vendor-defined messages that enable the use of existing UCIe sideband channels to send low-speed, low-priority communication between dies without encumbering the main data path. Instead of interrupting the high-bandwidth path with this type of traffic, a die can use the UCIe sideband to send commands such as telemetry and interrupts to the other die.
  • Hardware-based bring-up that speeds up initialization without needing to load heavy firmware on the remote chiplet. If UCIe link bring-up would require heavy firmware to be loaded into the die, a separate path would be required to load the firmware. From a design, hardware, and time perspective, this can be wasteful and is best avoided.
  • A pre-verified design reference flow that is achieved by integrating the UCIe IP with Synopsys 3DIC Compiler and all the required design collateral and documentation such as automated routing flow, interposer studies, and signal integrity analysis.
  • Standard and advanced packaging technology support that gives flexibility to customers, making it easier to integrate and benefit from cost trade-offs. In the past, advanced packaging technology supporting high-density routes and bandwidth meant high expenses. With evolving packaging technology bringing costs down, SoC designers can use complex and advanced packaging at a more affordable level. Synopsys alleviates that trade-off by fundamentally enabling higher bandwidth in the same area and offering a cost-effective solution to support both packaging technologies.
  • An automotive UCIe IP that meets the need for ADAS chips, leveraging the multi-die architecture for more advanced functionality. SoC designers can leverage the integrated SIM sensors and test and repair functions to build a more reliable SoC, addressing the demanding automotive requirements.
  • AXI, CHI C2C, CXS, PCIe, CXL, and streaming that are available to address the needs of a diverse set of use cases and applications, ranging from streamlined and low-latency connections between compute fabrics in two dies to higher interoperability and leveraging existing software ecosystems with CXL and PCIe protocols.

Synopsys is leading the way in developing high-quality UCIe IP and enabling multi-die design success, offering silicon proof points across various foundry nodes for advanced and standard package technologies. As an active member of the UCIe Consortium, Synopsys enables successful ecosystem interoperability by maintaining compliance with the UCIe specifications. Today¡¯s upgrade to 40Gbps further helps customers adapt to the demands of data-intensive applications and achieve efficient high-bandwidth die-to-die connectivity.

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