Introduction

In today’s semiconductor industry, demand for high-density, high-speed mixed-signal designs is increasing—particularly in Radio Access Network (RAN) applications where RF, analog, and digital components must work seamlessly together. This case study highlights how izmomicro designed and fabricated a 22-layer RF System-on-Chip (SOC) board. The project showcased expertise in PCB layout, signal and power integrity, and thermal analysis—while meeting strict size, performance, and reliability requirements.

Project Context and Objectives

The client required a custom RF SOC board for RAN systems, with the following goals:

• Development of a 22-layer PCB using Cadence Allegro.
• Support for mixed-signal design (60% digital, 40% analog) with 10 GHz transmission and optical interfaces
• Integration of 9250 nets, 20 BGAs, and 2250 components.
• Use of a Xilinx Cyclone Sync Ultrascale+ FPGA for performance optimization.
• Robust SI/PI design for DDR4, SRAM, RF, QSPI, RGM-II, and SFP+ modules.
• Thermal stability and noise minimization within 200 mm x 300 mm constraints.

Key Challenges

The project involved multiple technical hurdles:

• Compact design requirements - fitting thousands of components into limited board space.
• Mixed-signal coexistence - ensuring RF, analog, and digital logic worked without interference.
• High-speed integration - co-designing RF frontends, ADCs, memory, and optical interfaces.
• Noise reduction - mitigating crosstalk, impedance mismatches, and PDN noise.
• Single-spin fabrication - achieving first-pass success without multiple iterations.

Design and Implementation

PCB Layout & Materials Using Cadence Allegro, the team designed a 22-layer board with Megtron 6 material for superior high-frequency performance and reliable routing.

Signal Integrity (SI) Analysis Extensive Cadence Sigrity simulations validated performance across write/read operations, setup/hold timing, control signals, and clock measurements. IBIS, SPICE, and S-parameters confirmed robustness with TDR, eye diagrams, and impedance checks.

Power Integrity (PI) Analysis PDN AC/DC analysis ensured clean power across voltage rails. DCDC drop studies and impedance plots confirmed stable power delivery.

Thermal Analysis Ansys Icepack simulations verified effective heat dissipation, maintaining performance under dense, high-speed operation.

Advanced Manufacturing Expertise The parts were manufactured at our state-of-the-art class 1000 Cleanroom IC Packaging facility in Bangalore.

Overcoming Challenges

• Optimized Layout - Multi-layer routing minimized space usage while isolating analog and digital signals.
• RF + Digital Co-Design - Joint optimization of RF frontends, FPGA, and optical interfaces improved overall performance.
• Noise Mitigation - Back-drilled vias and careful PDN planning reduced crosstalk and noise.
• Pre-Fabrication Validation - High-fidelity simulations minimized risk and enabled first-pass fabrication success.

Solution Delivered

izmomicro successfully delivered a fully functional, first-pass 22-layer RF SOC board that met all client requirements:

• Optimized schematic and layout tailored to size and performance constraints.
• Seamless integration of RF, analog, digital, and optical modules.
• Verified SI, PI, and thermal performance through rigorous simulation.
• Use of advanced Megtron 6 material for reliable high-speed transmission.

Results & Impact

• First-pass fabrication success, reducing development time and cost.
• Enhanced RAN system performance with reliable communication and data handling.
• A scalable methodology for future high-density, high-speed SOC boards.
• Strengthened izmomicro’s position as a trusted partner for advanced semiconductor and RF system design.

Conclusion

This project demonstrates izmomicro’s ability to manage complex high-speed board designs under strict constraints. By delivering a 22-layer RF SOC board that met size, performance, and reliability goals in a single spin, izmomicro reaffirmed its expertise in mixed-signal integration, advanced simulations, and first-time-right semiconductor solutions. For organizations seeking end-to-end PCB and semiconductor design services, izmomicro offers the tools, experience, and technical depth to deliver success in demanding applications.