SWRS273D November 2021 – September 2024 AWR2944
PRODUCTION DATA
The device clock subsystem generates 76 to 81 GHz from an input reference of 40 MHz crystal. It has a built-in oscillator circuit followed by an Analog PLL and a RF synthesizer circuit. The output of the RF synthesizer is then processed by an x4 multiplier to create the required frequency in the 76 to 81 GHz spectrum. The RF synthesizer output can be modulated by the timing engine block to create the required waveforms for effective sensor operation or it can input a fixed signal of 1GHz directly from APLL.
The Analog PLL also provides a reference clock for the host processor after system wakeup.
The clock subsystem also has built-in mechanisms for detecting the presence of a crystal and monitoring the quality of the generated clock.
Figure 7-2 describes the clock subsystem.