Concerns about heat and rapid temperature shifts are also removed with MEMS oscillators. Developers using the higher-performance MEMS OCXOs should assume that their local timing source will operate cleanly up to 125ºC with very tight stability. MEMS OCXOs will also maintain frequency within specifications even if ambient temperature changes by as much as 20ºC within minutes. The timing source will not suffer any environmentally-induced fast frequency changes that can lead to dropped connections. It will be possible to give operators confidence that they can deploy 5G radios wherever they are needed.
The programmability of MEMS timing also redefines 5G design best practices. MEMS OCXOs expand the choices that developers have with regards to frequencies, output types, operating temperature, in-system control and other features. For example, developers can now choose the optimal frequency for the application, from 1 to 220 MHz and anywhere in between. They also can specify output types such as LVCMOS and clipped sine-wave to optimize board performance. Other options include extended temperature operation from -40 to +95ºC and -40 to +105ºC, I2C serial interface for in-system programmability and digital controlled oscillator mode instead of a traditional analog voltage-controlled oscillator (VCO).
These choices are not possible with quartz OCXOs, which are custom built from the ground up, have severe limitations on the capabilities that can be specified, and are difficult to procure and use. In contrast, MEMS OCXOs come in a variety of standard footprint choices and are available as drop-in replacements for legacy OCXOs while improving overall comparative system performance and robustness. Another advantage is faster startup time to the desired frequency – MEMS OCXOs get there in milliseconds while analog quartz-based OCXOs can take minutes.