VFTT – Analog Devices

582

by Benjamin Annino, Systems & Applications Director for the Aerospace and Defense Business Unit, Analog Devices

MPD: Please describe what you consider to be your company’s most significant technological achievements in 2022.

BA:

ADI is unique in its portfolio breadth and performance leadership across the entire signal chain from RF to bits, power, and precision. I’ll talk about how ADI is making a huge positive impact on aerospace and defense capabilities.

I think ADI’s most significant impact in 2022 has been the continued leadership in offering the full high performance signal chain solution for customers…and then making it easy to use with software enabled development platforms. ADI truly is a one-stop shop for the entire IC solution in most aerospace and defense signal solutions. This isn’t new, but we’ve continued to bolster our leadership in performance and breadth.

A new focus, and something that is improving rapidly, is the ADI software solution that wraps around the ICs and seamlessly plugs into the customer software ecosystem. This is especially important in high speed digitizer systems, which I’ll discuss later.

ADI made big strides in 2022 putting all the software and hardware pieces together to demonstrate software defined over the air phased array beamforming. By demonstrating performance using beam patterns as opposed to just IC parameters, ADI retires risk, reduces prototyping expense, and accelerates design cycle times for customers. Our goal is to integrate all the circuit pieces into a system platform, and then wrap an open software architecture that our customers are comfortable with around it.

A couple of platform examples for phased array are the quad-MXFE DAC/ADC platform, which demonstrates 16 transmit and 16 receive multi-channel, multi-chip phase synchronization, and the X-Band Phased Array Platform, which is a scalable phased array panel with planar RF beamforming electronics behind the panel. Using these two platforms, customers can prototype an X-band phased array system in hours.

MPD: Many technologies are driving RF and microwave technologies today. Which ones do you feel are the most important as it concerns your company’s work?

BA:

ADI’s design expertise and portfolio spans across many semiconductor technologies and process nodes. Each of them is optimal for a certain chip objective. I’ll give you several examples:

Silicon advances are allowing higher speed data converters with higher levels of digital integration on chip
ADI revolutionized the RF switch and digital attenuator market using MMIC SOI to replace discrete PIN diode circuits, while improving ease of use, size and performance
SOI up and down frequency converters that integrate amplifiers, mixers, attenuators, and digital control are replacing discrete mixer transmit and receive chains
GaAs remains a mainstay for LNA and driver amps and our portfolio continues to improve linearity and noise at smaller package sizes like 2mm
Our expanding wideband GaN portfolio delivers high power density that replaces vacuum tubes and large RF combining
Heterogeneous integration allows ADI to package all of these technologies together to offer the best all-in-one solution. A good example of this is transmit/receive switched chips that combine GaN, GaAs and SOI in a single SMT package.

Maybe not as obvious, but the power solution is the backbone of high performance RF systems, as it drives noise and size. For example in PLLs, low phase noise is the critical PLL spec. A noisy power supply will lift up the noise floor of a PLL, thus LDOs are usually used to power them. However these are lower efficiency compared to a switching regulator, and ultralow noise LDOs are limited to <1A (LT3045).

Hitting the market in 2022, the ultralow noise Silent Switcher 3 buck regulator family can achieve nearly the same phase noise performance as an ultralow-noise LDO.

In the example of an RF transceiver, key power supply attributes are settling time and switching frequency harmonics. The power supply needs fast settling after a load step, otherwise the LO phase will not be accurate for the Tx and Rx mixers, affecting both the beamforming accuracy and Tx EVM (error vector magnitude). Switching frequency harmonics can modulate the phase of the LO or clock, creating local spurs on Tx and Rx signals.

The Silent Switcher 3 architecture integrates a high gain error amplifier and this combined with external compensation provides ultrafast transient response to fast changing loads, avoiding degraded performance in demanding communications applications. Silent Switcher Regulators also help block high frequency spurious content (>1MHz) which LDOs cannot do.

Fast settling and ultralow low frequency noise provides the ability to directly power RF transceivers, replacing Buck+LDO solutions resulting in 75% smaller solution size, lower cost, higher system efficiency, and 50% MLCC content reduction.

Last but not least, the space market continues to expand on the back of LEO deployments, and 2022 saw space qualification of several key digitizer, low-noise amplifier & signal control components. Some highlights:

AD9213S (CS High) – 12 bit, 10Gsps RFADC (applications could be ultra-wideband datalinks or space-based radar)
ADL8142S (CS Low) – SATCOM Ku-band LNA (both package and die versions released, application could be phased array)
AD9361S (CS High) – Narrowband Transceiver (primary application is tracking, telemetry and control system on spacecraft)
ADH8411S (CS High) – Low Noise Amplifier, 0.01 GHz to 10 GHz AD9914S (CS Low) – 3.5 GHz Direct Digital Synthesizer (applications could be L,S, C, X-band uplink or space-based radar)
ADLT2852S (CS Low) – 20Mbps RS485/RS422 Transceiver
ADH347S – Aerospace GaAs, SPDT Switch, Non-reflective, DC to 14 GHz (LH5 Pkg), DC to 20 GHz (Die)
ADH365S – SMT MMIC Divide-By-4, DC to 13 GHz

MPD: If your company serves the defense market, what are you working on (that you can talk about)?

BA:

A big trend in the defense market is the desired platform convergence of radar phased array, electronic warfare, and military communications into multi-band and multi-function systems. Sensors are increasing exponentially as drones, phased array radars, and manpack systems proliferate (just to name a few). Think of your mp3 player, camera, phone, gps nav, and even desktop computer converging to one multi-function device that everybody owns. The hard part is accomplishing all-in-one functionality while reducing size, weight, power and cost and improving performance.

When you look at the overall electronic solution, the high speed digital data converter makes or breaks what you are trying to accomplish in multi-band, multi-function systems. It is the functional block that converts the analog physical world to digital bits, and the performance dictates how much bandwidth, range of RF spectrum, and dynamic range is possible. Dynamic range usually equates to how well you can detect a signal when it is really far away, or when somebody doesn’t want you to see it. ADI digital data converters lead the high performance market especially important to aerospace and defense and instrumentation, where customers want the highest instantaneous bandwidth at the best possible dynamic range. We are continuing to advance technology that improves noise and linearity across wider and wider RF bandwidths which is hard to do at the same time. Direct RF digitization widely exists today up through C-band, and there is a strong need to push this well past X-band. A few folks can claim to do this, but not with the excellent dynamic range of ADI converters. This is where ADI differentiates, taking that leading dynamic range and extending it over wider bandwidths at low power.

Direct RF digitizing higher bandwidths is great in that it simplifies and shrinks the RF front end, but you end up pushing the challenge into the digital realm. Now you need to process extremely wide high speed digital data streams while meeting difficult timing and power constraints. ADI is incorporating more and more DSP on-chip with the data converter to offer flexible software defined systems on chip. Starting with the MXFE series of data converter, the way to view the part is really as a digital signal processing ASIC with multi-channel DAC and ADC. You don’t write to registers anymore, you interface with a software package.

The most efficient phased array systems today combine RF and digital beamforming. That is why ADI continues to lead in highly accurate, wideband RF beamformers. Recently released in 2022, the ADAR4002 is a very low power broadband bi-directional single channel true time delay unit (TDU) and a digital step attenuator (DSA). This chip will allow wide IBW, high linearity beamforming across a very wide RF range important to multi-band radar and EW folks.

On the transmit side of things, a wide variety of defense systems need to deliver ever increasing RF transmit power in smaller form factors. GaN allows the power density and frequency bandwidth to accomplish this, and ADI continues to improve the portfolio breadth in this market. An example is ADPA1106 releasing in 2022. This S-band GaN PA delivers 40W at an excellent typical PAE of 56% and will be a popular solution in weather, marine, and military Radars.

Improving technology upgrade cycle times is another focus for defense in order to keep pace with faster emerging threats. There just isn’t enough time for defense primes to constantly design systems from scratch. ADI doesn’t just provide the ICs. We help customers put the whole solution together. We provide signal chain platforms and reference designs that put all the pieces together from the RF conditioning, data converter, FPGA, software, clocking, software stack, and even application layer so that customers can focus on hosting their mission algorithm on the turn-key ADI platform. Our customers want the full turn-key hardware and foundational software solution so that they can focus on their value-add mission solution. This can shave years off deployment time.

Looking at the big picture, I think ADI is unique in the breadth of its high performance IC portfolio from RF to digitization, but even beyond that our ability to deliver the full software defined signal solution. We can provide the whole IC parts list, and then put it together for you, too. This delivers a huge amount of value to our customers.

MPD: Technology appears to have advanced to the point where millimeter-wave deployment on a wide scale is possible. What is your perspective on this?

BA:

In 2022 ADI made remarkable advancements in the areas of 5GmmW network access, E Band backhaul and terminal satellite communications. Investment motivated by these markets significantly benefits cross-over products aimed at aerospace and defense applications like electronic warfare, radar and MILCOM. In 2023 we will see derivative products focused on the instrumentation and defense markets.

5G network access requires massive increases in data volume (x1000) and data rates that are 10 to 100x faster than its predecessor 4G. A foundational piece of the network will be mmW Access or what is known as FR2. 5GmmW expands on the existing FR1 spectrum which is <7.125GHz by opening up coverage within 24 GHz to 48.2 GHz. Within this FR2 spectrum channel, bandwidths of up to 1.6 GHz can be supported to deliver highest data rates to users.

Along with high performance access to these mmW frequencies, a core technical enabler will be in active phased array antenna technology. Here many radiating elements in each array will support multiple simultaneous data streams for higher capacity. ADI developed an entire chipset solution of highly integrated up and down converters, supported by high performance PLLVCO technology to gain access to the mmW spectrum. Also, ADI developed x16 channel (or dual polarised 2×8 channel) analog beamformers to give the needed multi element gain and phase control to implement beam steering. At Analog Devices, we achieved a wideband chipset solution that allows radio designs to cover the entire allocated FR2 spectrum with only x2 UDCs (ADMV1128 & ADMV1139) and x3 BFICs (ADMV4828, ADMV4928 and ADMV4728). This allows for common platform design objectives and future proof the release of systems.

E Band technology is becoming a necessary medium to allow 5G networks of the future transfer bi-directional data from network access points to the core network. E Band, which operates in the 70 & 80 GHz bands, offers a high capacity future proof technology that can deliver +10Gbps link speed which is required for next gen 5G RAN backhaul. E Band is a great choice to complement physical fiber optical links, because site acquisition and installation costs for wireless technology can be far less intensive. As 5G rollouts continue, a high capacity wireless backhaul solution such as E Band offers the network providers more scope in how they plan their networks. And in areas where fiber optic cable doesn’t exist, E Band wireless backhaul takes less time to deploy and can offer the better solution. ADI made cutting edge technological advancements in recent times in E Band chipset development by focusing on higher levels of integration, SMT package technology instead of bare die and the integration of a Waveguide in package which removes design complexity for IC to PCB transition at mmW frequencies. ADI is continuing to work on further advancements in this family of E Band solutions with more announcements to come in 2023!

Within the domain of terminal SATCOM ADI released some notable highly integrated terminal up and down converters for the next generation of LEO connectivity. LEO satellites are promising to deliver high capacity, reliable Internet connectivity and will play an important role in the continuing rollout of 5G cellular networks. Orbiting between 500km to 2000 km above the Earth’s surface, LEO constellations will deliver technically superior low latency high-capacity broadband connectivity versus their higher orbiting satellite counterparts. We see remarkable advances in semiconductor technology within ADI to deliver performance and integration benefits while minimizing footprint and lowering the cost to deploy. ADI recently released a family of up & down converters for Ku- and Ka-Band user terminals. They address the most difficult SWAP-C (Size, Weight, Area, Power, Cost) concerns in this commercial high volume market space. These UDCs (PN’s: ADMV4630/ADMV4640 & ADMV4530/ADMV4540) contain extensive RF & IF signal conditioning such as filters, amplifiers, attenuators, PLLVCO and power detection. All ICs are purposely designed with the signal chain performance of a user terminal in mind.

Furthermore, ADI released a new Ku- Band BFIC (ADMV4680) for terminals that will enable ESA (Electronic Steerable Antenna). LEO constellations will have many satellites that move in and out of the ground terminal field of view so it’s far more efficient to use ESA, as it can enable high directivity by electronically steering the transmit and receive beam of energy in the direction of the satellite. This BFIC is a truly remarkable release as cost, system performance & size (IC = 8.2mm2) are all optimized. In fact, core to the development of this BFIC technology to minimize overall radio cost is system and array expertise. Mechanical assembly and PCB design, which includes stack up and number of layers, are part of the radio cost driver and ADI has strong expertise to complete this work.

I want to thank the following ADI folks for writing sections of this View From the Top: Alison Steer (silent switchers), Donal McCarthy (mmW), Keith Benson (Amps), Chris Chipman (Space).

(582)