Obsolescence of semiconductor components within electronic subsystems is a very real and ever present threat to every electronics design engineer. A timely reminder of this truth came to EM Solutions when they released their wideband Ka nanoBUC HUB back in 2014. As EM Solutions marketing personnel were launching a new range of wideband GaN products based around this core technology, certain key suppliers were busy announcing changes of their own. Analog Devices’ acquisition of Hittite, and Triquint’s merger with RFMD created a ripple effect throughout the electronics industry, not least upon EM Solutions’ new range of BUCs. These products relied upon unique cutting-edge microwave components, which suddenly were made obsolete by this merger activity.
Fortunately the obsolescence was rolled out gradually and last time purchases gave EM Solutions a chance to buy more time while they considered their options. The biggest hurdle to overcome was not the amplifiers in the BUC transmit chain or the MMICs used for the oscillators, but a variable frequency filter, used in the local oscillator (LO) driver chain. The unavailability of this part caused a major rethink on the operation of EM Solutions’ dual-band BUC upconverter architecture.
Rather than dwell on the demise of a beloved component, EM Solutions seized the opportunity to benefit from the latest innovations in synthesiser technology from Texas Instruments, and create an LO chain operating at twice the previous operating frequency. This not only created the potential to improve the product’s spurious performance, but also to enhance its already low-phase noise design.
These forced enhancements to the product line are now in place for the latest production models and will further improve reliability and performance for which EM Solutions products are renowned.
Other ongoing R&D efforts on the nanoBUC product line include adding digital control to the gate circuitry. It has been found that small temperature variations of the gate voltage of the GaN MMICs create significant changes in their quiescent current, which can subsequently cause deviations in the linear output power. These variations can be corrected by the lineariser circuit; however it has been found that adjusting the quiescent current over temperature does lead to improved repeatability of the intermodulation products and hence better linear power.
Component obsolescence causes significant pain to the design engineer. But properly overcome, it can bring new innovation and improved performance to the customer, as it has with EM Solutions newest BUC products.
