IC Substrate - Microwave RF performance full frequency coverage, extensive semiconductor technology

Semiconductor materials have gone through three stages of development, including the first generation of semiconductor materials represented by silicon (SI) and germanium (ge); to compounds represented by gallium arsenide (GaAs) and indium phosphide (InP) The second stage, and the third generation of wide-bandgap semiconductor materials based on gallium nitride (GaN) and silicon carbide (SiC). Especially with the evolution of communication technology towards high GHz frequency bands, the third-generation semiconductor material GaN, which has the advantages of low conduction loss and high current density, has attracted greater attention from the industry, which can significantly reduce power loss and heat dissipation load, and is widely used in frequency conversion. Fields such as chargers, voltage stabilizers, transformers, wireless charging, etc.

However, there is no universal methodology in this world. The same is true for the semiconductor process materials of the radio frequency and microwave side of wireless communication: CMOS's low power consumption, high integration, low cost and other advantages are still significant; GaAs has excellent physical performance advantages in the field of high power transmission; and SiGe process compatibility The advantages of GaN are outstanding, and it is compatible with almost all new process technologies in the silicon semiconductor VLSI industry; GaN has unique advantages in the application of high-frequency, high-temperature, and high-power radio frequency components. In fact, ADI, as one of the world's leading semiconductor providers of high-performance radio frequency and microwave technology, has also laid out almost all of these mainstream semiconductor processes in its wide product line covering DC to 100GHz. To occupy the front-end of high-performance radio frequency microwave technology, it is obvious that a combination of multiple process technologies is required to enter the battlefield.

SiGe process achieves 24GHz to 44GHz microwave up/down converter
Not long ago, ADI announced the introduction of highly integrated microwave up-converters and down-converters ADMV1013 and ADMV1014. These SiGe process-based ICs work in an extremely wide frequency range from 24GHz to 44GHz, making it possible to support all 5G millimeter wave bands (including 28GHz and 39GHz) on a single platform built, thereby helping to simplify design and reduce costs.

In addition, the chipset can provide a flat 1GHzRF instantaneous bandwidth, supporting all broadband services and other ultra-wide bandwidth transceiver applications. Each up-converter and down-converter are highly integrated, including I (in-phase) and Q (quadrature-phase) mixers. The on-chip programmable quadrature phase shifter can be configured to directly convert to/from baseband (operating frequency) Range: DC to 6GHz) or frequency conversion to IF (operating frequency range: 800MHz to 6GHz).

The chip also integrates a voltage variable attenuator, transmitting PA driver (in the up-converter) and receiving LNA (in the down-converter), LO buffer and programmable tracking filter with integrated 4-times multiplier. Most programmable functions are controlled via the SPI serial interface. Through this port, these chips also provide unique functions for each up-converter and down-converter to correct their respective quadrature phase imbalance, so it can improve the sideband emission performance that is usually difficult to suppress, and improve 10dB or more from the typical value of 32dBc . In this way, it can provide unmatched microwave radio performance. The combination of these features provides unprecedented flexibility and ease of use, while minimizing external components to support the realization of small-scale systems such as small cells.

The highly integrated ADMV1013 microwave up-converter and ADMV1014 microwave down-converter are very suitable for microwave radio platforms operating in the 28GHz and 39GHz 5G wireless infrastructure frequency bands. These converters have a bandwidth of 1GHz, and an upconverter with an OIP3 higher than 20dBm, can support stringent modulation schemes (such as 1024QAM), and can support multi-Gb wireless data. In addition, the chipset also supports other applications, such as satellite and ground receiving station broadband communication links, aviation radio, RF test equipment and radar systems. Its excellent linearity and image rejection performance are especially suitable for increasing the range of microwave transceivers.

Traditional materials rejuvenate, 28nm CMOS process leads RF technology innovation
In spite of the endless emergence of various new materials and technologies, in recent years, CMOS-based innovative wireless solutions still show dazzling performance from time to time. Among them, ADI has launched a number of high-performance products that have attracted wide attention. 28nm high-speed CMOS analog-to-digital converter AD9208 for wideband software-defined system, aimed at 4G/5G multi-band wireless communication base station and 2GHz E-band microwave point-to-point backhaul platform for gigahertz bandwidth applications. 28nm high-speed digital-to-analog converter series AD9172, announced not long ago that it once again launched a new AD9081/2 MxFE platform based on its 28nm CMOS.

The AD9081/2 MxFE platform allows manufacturers to install multi-band radios on the same board area as single-band radios, increasing the call capacity of today’s 4G LTE base stations by 3 times. With 1.2GHz channel bandwidth, the new MxFE platform also supports wireless Operators add more antennas to their cell towers to meet the higher radio density and data rate requirements of the emerging millimeter wave 5G. The AD9081/2 MxFE device integrates 8 and 6 RF data converters respectively, realizing the industry's widest instantaneous signal bandwidth (up to 2.4GHz), reducing the number of frequency conversion stages and relaxing filter requirements, thereby simplifying hardware design And by reducing the number of chips to solve the problem of space constraints faced by wireless device designers, making the printed circuit board area reduced by 60%.

Distributed power amplifier based on GaAs
Gallium arsenide technology is a commonly used technology in the design of radio frequency and microwave devices. If your design exceeds 40 GHz, and may reach 80 or 90 GHz, then gallium arsenide seems to be the only option currently. Power handling, insertion loss, isolation, and linearity are design parameters, and both silicon and gallium arsenide processes can meet the requirements. For high temperature work, gallium arsenide shows superior performance to silicon. In addition, the gallium arsenide pHEMT device can also achieve functions such as fail-safe operation, but the device requires a power source to enter the conductive mode.

ADI's GaAs-based distributed power amplifier product HMC994A has an operating frequency range of DC to 30GHz. The device covers dozens of bandwidths, many different applications, and can achieve high power and efficiency. Its performance is shown in the figure. Here, we see that it is a device with a saturated output power greater than 1 watt with a typical power added efficiency (PAE) value of 25% covering MHz to 30 GHz. This product also has a powerful third-order intercept point (TOI) performance with a standard value of 38dBm. The results show that the use of GaAs-based designs can achieve efficiency close to many narrowband power amplifier designs. HMC994A has a positive frequency gain slope, high PAE broadband power performance and strong return loss, which is a unique product.

The relationship between HMC994A gain, power and PAE and frequency.

GaN broadband power amplifier with outstanding power advantage
ADI has introduced a standard product HMC8205BF10, which is based on GaN technology with high power, high efficiency and wide bandwidth. The product's working power supply voltage is 50V, it can provide 35W RF power at 35% of the typical frequency, with a power gain of about 20dB, covering dozens of bandwidths.

In this case, compared to similar GaAs solutions, engineers only need an IC to provide about 10 times higher power. In the past few years, this may require complex GaAs chip assembly schemes, and the same efficiency cannot be achieved. This product demonstrates the various possibilities of using GaN technology, including covering a wide bandwidth, providing high power and high efficiency. This also shows the development history of high-power electronic equipment packaging technology, because this flange-encapsulated device can support the continuous wave (CW) signal required by some special applications.

Summarize
In summary, various semiconductor materials have their advantages. Today, with the increasingly extensive coverage of wireless devices, mainstream semiconductor process technology-related products can play their unique advantages in various applications: based on factors such as power consumption and cost, consumer terminals Products are obviously more using CMOS technology; CPE uses CMOS and SiGe BiCMOS; low-power access points use CMOS, SiGe BiCMOS and GaAs; and the field of high-power base stations is the world of GaAs and GaN. With the widespread advancement of 5G deployment, this trend will continue.