Selection reference · illustrative scenario
Confirm the MCU clock mode
Internal oscillation, an external crystal and an external clock input are different paths. Check the MCU guide before selecting a passive crystal, LVCMOS source or other architecture.
Engineering: review the oscillator loop
Match CL, ESR, drive and package to the host and parasitics. For an active source, check input thresholds, amplitude and sequencing; a software-mode change alone does not establish electrical compatibility.
Procurement: preserve suffixes and revisions
The same frequency and size can have different loading or temperature options. Attach the current datasheet and full code, and carry the approved identity into purchasing records.
Scenario: validating a smaller package
A smaller footprint requires more than a pad-space check. Compare ESR, CL and drive conditions, then test start-up across supply and temperature corners on multiple boards before approval.
Inquiry & validation checklist
- Host and clock mode
- Frequency, CL, ESR and drive
- Package and footprint constraints
- Power-up and temperature tests
