SNAU297 July 2025 LMK5B12212 , LMK5C22212A
For flexibility, the EVM provides additional XO input options (use one at a time). C70 allows an external reference to be provided at SMA connector XO (J8). C71 allows one of the onboard XO/TCXO/OCXO footprints to be used.
By default, Y1 is populated with a 48MHz TCXO and selected with the populated R43 and R206. R43 provides the output clock of Y1 to the XO pin of the LMK5B12212 and R206 provides power to Y1.
Y2 (2.5mm × 2.0mm) is populated with TI high-performance 48MHz BAW oscillator LMK6C. This BAW oscillator is not connected to the LMK5B12212. R46 must be populated to provide the output of Y2 to the XO pin.
Additional PCB footprints are available to install alternate components for performance evaluation of specific oscillators. These additional footprints are Y3 (3.2mm × 2.5mm), Y4 (9.7mm × 7.5mm), Y5 (25mm × 22mm), and U4 (2.5mm × 2mm).
When using Y2, Y3, Y4, Y5, or U4, R43 and R206 must be removed to power down and isolate the output of Y1. When populating Y3, R47 must be populated to provide the output of Y3 to the XO pin. When populating Y4, R48 must be populated to provide the output of Y4 to the XO pin. When populating Y5, R49 must be populated to provide the output of Y5 to the XO pin. When populating U4, R50 must be populated to provide the output of U4 to the XO pin. Section 5.1.8 shows the components described above.
Take care if more than one device is installed to remove resistors to power down unused oscillators and isolate the outputs as described above.