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Advanced driver assistance systems (ADAS) applications rely on an array of technologies, a key one being automotive radar operating at 77GHz to 81GHz. Phase-locked loops (PLLs) are at the heart of radar, providing local oscillator (LO) frequency to the radar transmitter and receiver (transceiver). For a PLL to be effective in radar detection and communication, its frequency accuracy must be high and its phase noise must be low.

CoreHW, a fabless semiconductor company established in 2013 in Finland, has achieved an 80GHz millimeter wave PLL (MMW PLL) with superior phase noise performance. Developed with the Synopsys RFIC design flow on the GlobalFoundries (GF) 22FDX? process technology, the MMW PLL IP is ideal for applications including autonomous driving, 5G/6G communication, IoT networks and other hyper-connectivity systems, and aerospace and defense systems. 

Read on for more details about the challenges of advanced RFIC designs, and how a modern, open RFIC design and verification flow can accelerate the path to silicon success. 

Advantages of Higher mmWave Frequency Bands

PLLs serve as a frequency source in radar and communication systems. For example, in an automotive radar system, the radar installed at the front of the vehicle emits an RF wave beam that scans the space ahead. Objects will reflect the wave back to a radar receiver, which detects objects for collision control. The PLL creates a reference signal to upconvert a baseband signal to mmWave frequency for transmission, and downconvert the received signal to baseband for target echo processing.   The PLL must have low phase noise in order to identify slow-moving objects such as pedestrians walking at street intersections.

PLLs play a similar role in wireless communication devices such as the smartphones and base stations. Lower frequency radio waves are easier to generate. Bluetooth and WiFi, for example, typically operate in 2.4GHz and 5GHz bands. However, lower frequency bands are crowded with limited spectrum availability. New applications are moving toward higher frequency mmWave bands, where there is greater spectrum availability along with more bandwidth, translating to finer spatial resolution in radar applications and higher rate data transmission in communication applications. The challenge, however, lies in generating a good quality signal with frequency purity. When the frequency source is not very pure, the signal that echoes back can be difficult to detect, hampering the effectiveness of the end application.

CoreHW¡¯s MMW PLL IP consists of a high-accuracy fractional N PLL frequency synthesizer with low-noise voltage-controlled oscillator (VCO). It can synthesize a low phase noise carrier for demanding wireless communication networks as well as fast-chirp frequency modulated continuous wave (FMCW) waveforms for various radar systems. The PLL IP fundamentally operates at 19GHz to 20.25GHz, while frequency multipliers can convert the waveform to radar frequency bands at 76GHz to 81GHz and 76GHz to 81GHz. Its scalable architecture enables the IP to be customized to various mmWave wireless communication frequency bands.

RFIC Design Flow for Faster, Better Chip Design

Designing advanced RF and mmWave ICs continues to come with complex design requirements. In addition to the complexity of the chips themselves, the . Yet, analog and RF teams continue to face aggressive time-to-market pressures. To meet these requirements while also achieving accurate, repeatable results for a more efficient design and verification cycle, CoreHW used the Synopsys RFIC design flow on GlobalFoundries 22FDX process technology. The flow, certified for GF 22FDX, is based on Synopsys Custom Compiler? design environment for full custom analog, custom digital, and mixed-signal IC designs and Synopsys PrimeSim? unified workflow of next-generation circuit simulation technologies. Process design kits (PDKs) are available from GF for these tools. The flow is integrated with electromagnetic (EM) analysis tool, enabling designers to easily run interactive EM-circuit co-simulation for tuning and optimization.

"The RF and mmWave design flow we are deploying, based on Synopsys Custom Compiler and PrimeSim circuit simulator, along with the Keysight RFPro electromagnetic simulator integration, provides our designers an accelerated predictive process for the creation of high-quality, full-custom RF and millimeter wave mixed-signal ICs,¡± said Tomi-Pekka Takalo, CEO of . 

In short, the Synopsys RFIC design flow provides a complete front-to-back toolset that takes designers into the modern era of RF and mmWave IC design and verification with faster and better results.