Systems, methods, and assemblies to provide clock signals to electrical components of downhole tools are provided. In one example, an oscillator assembly may include a silicon-based oscillator having a variable capacitor circuit. The silicon-based oscillator may provide an output signal at a frequency within a range of frequencies. The oscillator assembly may also include control circuitry electrically coupled to the silicon-based oscillator. Moreover, the control circuitry may include a temperature input that receives a temperature corresponding to the silicon-based oscillator. The control circuitry may also include a control signal output electrically coupled to the silicon-based oscillator. The control signal output may be used to change a capacitance of the variable capacitor circuit based on the temperature received by the temperature input to maintain the output signal of the silicon-based oscillator within the range of frequencies.