RF/mmWave Wave System Requirements
Commercial Sector Requirements:
Successful RF/mmWave ASIC designs begin with a detailed understanding of the system requirements. RF systems between 700MHz and 6GHz are already part of our daily lives in smartphones, GPS, WiFi, and Bluetooth and have proven that low power miniature RF systems on advanced process nodes are feasible. New applications at mmWave frequencies based on very narrow transmission beam widths are creating similar game-changers. The short signal wavelength at these frequencies, coupled with advances in semiconductor processes, packaging, and antenna technology allow precise beams to be steered in miniature form factors enabling a whole range of applications. In the commercial world, these include multi-Gbps data links for wireless backhaul, 5G high-speed data connections, portable satellite terminals and high-speed internet to rural locations. The ability to transmit, steer and receive narrow beams enables the next generation of automotive radar required for driverless cars. The unique characteristics of mmWave signals allow for high resolution discrimination of metal or dense objects from softer human tissue and enable a new generation of security scanners to protect airports, industrial facilities, and schools. Such systems can also be used in novel diagnostic or health monitoring in a nonintrusive way.
Defense Sector Requirements:
Commitment to spectral dominance and the requirement to neutralize rapidly evolving asymmetric threats at multiple frequencies has led to a revolution in how RF/mmWave systems are conceived, developed and utilized. The ability to sense and understand the surrounding spectrum and characterize emitter locations, signal types requires precision navigation and timing information, high-fidelity data exchange and networked sensors. Software-defined radio systems are becoming much more prevalent, waveforms can change instantly, driving the need for signals intelligence and spectrum awareness systems to become much more adaptive. New signals need to be characterized on the fly. RF/mmWave systems need to be converged to utilize the same antenna subsystems on increasingly space and power constrained systems. Unmanned aerial vehicles can no longer afford a dedicated radio device, signals intelligence sensor, and electronic warfare sensor. These functions need to be integrated with each other to reduce the overall size, weight, and power (SWaP) which is required on a tactical platform.
What makes RF/mmWave requirements unique?
All these emerging systems operate with multiple RF/mmWave ASICs tightly coupled to the antenna subsystem with integrated packaging of printed circuit boards in the presence of high-speed digital subsystems for signal processing, and command and control. Antenna arrays for millimeter-wave systems create extraordinarily narrow beam widths and are mounted orthogonally on PCB substrates together with RF/mmWave ASICs. These systems typically have significant trade offs in performance, cost and power consumption making the choice of optimum process technology both critical and challenging. Experience with a range of advanced nodes on SiGe, SOI, FinFET, GaAs PHEMT, GaN is extremely valuable in defining the overall system solution and executing and subsequent development
Intrinsix has experience in the diverse range of subsystems required in RF/mmWave systems. Here are a few examples of our work:
High Performance Synthesizers and PLLs
- High performance LO/clock generation for 900MHz, 2.4GHz and 5GHz transceivers
- 1-6GHz Delta-Sigma fractional N PLLs
Phase and Time delays
- 6-bit phase shifters using vector modulators and true time delays to 60GHz
- Programmable and all pass true time delay subsystems to 60GHz
Transmit and Receive Signal Chains
- Dual band L1/L2 GPS (1.228/1.575GHz) receivers
- Bluetooth Low Energy (BLE), Zigbee transceivers
- RFID readers and OFDM modems.
- Ultra-Wide-Band transceivers
- Ultra-low power and ultra-wideband transceivers for medical applications
Wireless Charging ASICs
- RF to DC and DC to RF converters in CMOS, SiGe, GaAs, GaN
Custom RF/mmWave ASIC Design
- Full turn-key RF/mmWave ASIC designs for advanced architectures uniquely suited to wideband software definable RF systems.
- ASIC architecture, custom IP block and chip level physical and electrical design, application support and bring up.
- Supply Chain Management for foundry, packaging, and test.
RF/mmWave Design Platforms
The foundation of any successful RF/mmWave ASIC development is the background building block IP at all levels of abstraction targeted to support a wide range of foundries. Intrinsix “Jump Start kits” contain the collective design wisdom of multiple RF/mmWave projects and the Intellectual Property critical in avoiding a “start from scratch” scenario on each design. These kits provide the starting point for block level design in RF/mmWave systems such as communication links, beam forming networks, phase array systems or low power designs. Intrinsix has a comprehensive array of Jump Start IP which typically include schematics, test benches and some initial layout.
Summary of Jump Start Kits for RF/mmWave Semiconductor Design
PLL Jump Start Kit
- Process agnostic PLL models in Cadence
- Phase noise, RMS jitter, loop analysis, transients
VCO Jump Start Kit
- Multi core VCO design
- Can be combined with PLL kit to model a full PLL
LNA Jump Start kit
- Low power and high linearity LNA’s in multiple bands
T/R Switch Jump Start Kit
- Switch insertion loss, linearity and isolation trade off
Mixer/Multiplier Jump Start Kit
- Mixer conversion loss vs LO drive
- Multiplier 1/f noise
Power Amplifier Jump Start Kit
- Output Power, PAE, linearity and ACPR
Phase Delay and Time Delay Jump Start Kits
- mmwave phase and true time delay
- Alternative design approaches for SOI, SiGe processes
Using RF/mmWave Jump Start Kits:
Traditional RF design and especially mmWave design is unique in the sense that physical parasitics significantly affect performance. Unfortunately, this means that RF blocks do not easily transport from one process to another and a realistic model of the impact of layout needs to be included in early stages of the design to optimize the overall ASIC performance. This layout related information can be included in Jump Start Kit schematics in the form of schematic par models which include critical parasitic elements based on prior physical design experience. If required, block level physical layouts can be extracted or simulated with full EM simulation tools to provide detailed estimates of the impact of layout.
Test Chips and Testability:
At mmWave frequencies it is especially important to design for testability at the block as well as the chip level. This has led to the notion of test chips which contain current and future building blocks. These test chips are vehicles for testing new ideas – switchable tuning elements (L&C), coupled differential structures, lower loss phase shifters, matching circuits etc. They serve to de-risk complex mmWave IC development by obtaining verification of critical building blocks in a low risk and cost-effective manner. These test chips also have all the necessary calibration and de-embedding blocks required for high frequency testing.
RF/mmWave Design and Verification Flow
RF/mmWave ASICs are no longer simple stand-alone devices with static control configurations. Traditional systems consisted of a simple cascade of blocks and block specifications such as gain, SNR, and linearity were determined from simple cascade analysis. Modern systems contain complex interdependent signal flows with system level interactions between multiple RF and baseband controller devices. Signal flows cross multiple devices, transmission media and package interfaces. Top level design requires co-simulation of multiple devices for performance, functionality, and timing. System performance often depends on post calibration results that cannot easily be defined by simple pre-calibration simulations. In many cases, a full up system simulation is required to develop and define appropriate system specifications. Intrinsix has developed a robust RF/mmWave design flow refined from many designs over many years.
RF/mmWave systems with increasingly sophisticated requirements mandate a simultaneous “tops down” and “bottoms up” design flow where the performance and functionality of the overall design can be continuously verified as the block level designs evolve. The initial block level designs are derived from available Jump Start Kits or in some cases developed from scratch. These blocks are floor-planned early in the design cycle and the impact of any layout affects is anticipated. The initial focus is on the critical blocks that have significant impact on system performance. In parallel with the initial block design effort, system level test benches and performance verification flows are established so that requirements can flow down to the blocks and performance results can be rolled up to the top level.