SPRADO3B December 2024 – September 2025 AM620-Q1 , AM623 , AM625 , AM625-Q1 , AM625SIP
A low frequency (32.768kHz) WKUP_LFOSC0 is supported by the processor family. Based on the use case, a 32.768kHz external crystal + internal oscillator can be used as the clock source or an external 1.8V LVCMOS square-wave digital clock source can be used.
WKUP_LFOSC0 has limited use cases and can be optional. When WKUP_LFOSC0 is not used, the recommendation is to connect the WKUP_LFOSC0_XI to VSS and to leave the WKUP_LFOSC0_XO unconnected. For more information on connecting the unused WKUP_LFOSC0, see the WKUP_LFOSC0 Not Used section of the processor-specific data sheet.
For more information, see the following FAQs:
[FAQ] AM625 / AM623 / AM620-Q1 / AM625-Q1 / AM625SIP : LFOSC usage in the processor
The recommendation is to place the discrete components used to implement the external crystal based oscillator close to the WKUP_LFOSC0_XI and WKUP_LFOSC0_XO pins. For the crystal, the load capacitance selected is recommended to be in the range specified in the WKUP_LFOSC0 Crystal Electrical Characteristics table of the processor-specific data sheet. There is no requirement to add the PCB capacitance to the load capacitance.
The figure WKUP_LFOSC0 Crystal Implementation in the processor-specific data sheet shows the recommended crystal circuit. TI recommends that preproduction printed-circuit board (PCB) designs include the two optional resistors Rbias and Rd in case these are required for proper oscillator operation when combined with production crystal circuit components. In a number of use cases, DNI or delete Rbias and Rd is a 0Ω resistor. The resistors option can be removed from production PCB designs after evaluating oscillator performance with production crystal circuit components installed on preproduction PCB.