LMX2820 and LMX2594 Phase Noise Comparison

This technical report compares the LMX2820 RF synthesizer with internal doubler to the LMX2594 RF synthesizer, focusing on their phase noise performance and sub-harmonic spur characteristics. The LMX2594 operates within a frequency range of 7.5GHz to 15GHz, while the LMX2820 operates from 5.65GHz to 11.3GHz, extending up to 22.6GHz due to its internal doubler. The report details a phase noise comparison conducted at 13.2GHz, highlighting the performance differences between the two devices. The LMX2820 generally exhibits improved phase noise performance, particularly at close-in frequencies. However, the LMX2594 shows a slight advantage at high frequency offsets above 10MHz. Additionally, the report discusses the sub-harmonic spur performance of the LMX2820, noting that it benefits from integrated sub-harmonic filtering, while the LMX2594 does not generate sub-harmonic spurs. The conclusion emphasizes the overall better performance of the LMX2820 in specific scenarios.