Nitin Sharma, Sr. Director
Marketing and Applications, RF Transceivers, Analog Devices
Systems-on-a-chip (SoCs) have become indispensable in today’s designs, powering applications ranging from cellular infrastructure and radar to test-and-measurement equipment, among many others. SoC types include highly integrated RF transceivers that combine RF, mixed-signal, and digital sections in a single device. Such devices, in some instances, can slash the amount of required external components and ultimately reduce costs.
Currently, the Internet of Things (IoT) is prompting chip makers to develop SoC-based products to support a vast amount of requirements. SoCs will also need to satisfy more difficult requirements in the future, such as the challenges associated with upcoming 5G networks.
“5G and massive multiple-input, multiple-output (MIMO) are driving the need for denser, lighter, smaller, and more power-efficient base stations,” says Nitin Sharma, senior director of marketing and applications for the RF Transceiver product line at Analog Devices. “SoC solutions need to address this by means of higher levels of integration, wider bandwidths, and lower power consumption.”
SoC Challenges and Capabilities
Designing SoCs does not come without its challenges. For example, sensitive RF/analog circuitry must be protected from noisy digital circuitry to ensure acceptable spurious performance.
“Jointly locating sensitive RF/analog circuitry and large digital blocks is certainly one of the most challenging tasks,” says Sharma. “As the RF performance requirements increase to meet market demands, focus needs to be on spurious performance. With multiple power supplies, attention is required to ensure that sensitive analog circuits are protected from digital blocks that are large and noisy. In addition, with the inclusion of multiple high-performing phase-locked loops (PLLs), isolation between the voltage-controlled oscillators (VCOs) becomes critical. Without proper design techniques, these issues could generate undesired spurs that could severely limit the performance and flexibility of the end product.”
Engineers at Analog Devices utilize various techniques to develop RF transceiver SoCs that can achieve wideband, spurious-free performance while maintaining isolation requirements. For example, the company’s AD9361 and AD9364 RF transceivers (Fig. 1), which are well suited for a broad range of applications, operate from 70 MHz to 6 GHz.
Many other companies produce SoCs to support multiple applications. Nordic Semiconductor, for instance, offers low-power wireless chips, as well as reference designs. Its nRF51822 and nRF52832 multi-protocol SoCs enable applications like Bluetooth Smart, among others (Fig. 2). Another device, the nRF9E5 SoC, is a multi-band, sub-1-GHz solution. The company stretches beyond simply SoCs by providing several development kits as well.
Broadcom also delivers chips that find homes in a wide range of applications. The company, which was recently acquired by Avago Technologies, just introduced the BCM43012 Wi-Fi/Bluetooth combo chip for mobile platforms and accessories. The chip integrates power amplifiers (PAs), low-noise amplifiers (LNAs), and power management, enabling bill-of-material (BOM) cost reductions and small system footprints. On top of that, battery life of the BCM43012 is as much as three times longer as previous Broadcom combo chips.