Benefits of Ultralow Noise Switching Regulator in Noise-Sensitive RF Applications

Featuring ultralow noise, high efficiency, small size, and high current, the novel ultralow noise switching regulator is very suitable for noise-sensitive RF applications, including 5G/wireless, defense, instrumentation, etc. The advanced switching regulator family with ultralow output noise, known as Silent Switcher 3, has even lower noise than most low dropout (LDO) regulators in the low frequency range (0.1 Hz to 100 kHz). This article investigates the challenges and system benefits of applying the ultralow noise switching regulator in noise-sensitive RF systems, compared to a traditional buck + LDO regulator solution. The investigation is based on two representative case studies of RF applications: a high-performance phase-locked loop (PLL) clock and an advanced high speed ADC system. With proper control loop and filter design, the novel single-stage solution based on an ultralow noise switcher saves PCB space and cost for customers and features a smaller solution size, simplified structure and higher efficiency, while still supporting excellent system performance.