SBASAO8A June 2025 – April 2026 DAC39RF20
PRODUCTION DATA
The Serdes PLL output frequency is realized using multiple VCO cores. The LC tanks provide good phase noise performance. The entire range of 8.125GHz to 16.25GHz, an octave, is covered with 4 different VCO cores. VCO calibration is required to obtain the correct frequency of interest.
A stable reference clock is required for calibration. Calibration begins after the PLL is enabled. During calibration, the PLL loop is disabled, and the VCO control voltage is driven to mid-scale. The calibration algorithm uses the frequency detector to determine if the VCO frequency is too high or too low.
When VCO calibration is completed (or skipped), and lock is detected, the PLL_LOCKED field is asserted.