AN2867 datasheet(40/41 Pages) STMICROELECTRONICS

40 / 41 page

Revision history

AN2867

40/41

DocID15287 Rev 9

19-Dec-2014

Updated Section 2: Oscillator theory.

Updated Section 3: Pierce oscillator design. Renamed section “Gain

margin of the oscillator” into Section 3.4: Oscillator transconductance

and content updated. Updated Section 3.6: Startup time. Updated

Section 3.7: Crystal pullability.

Updated Section 4: Guidelines for selecting suitable crystal and

external components.

Updated Section 5: Some recommended resonators for STM32

microcontrollers.

Added Section 8: Reference documents.

Updated Section 9: Conclusion.

19-Feb-2015

Updated Section 2.3: Negative-resistance oscillator principles to

specify the ratio between negative resistance and crystal ESR for

STM8 and STM32 microcontrollers.

Added Section 3.8: Safety factor.

Added Check the Safety Factor of the oscillation loop step in

Section 4.2: Detailed steps to select an STM32-compatible crystal.

Note moved from step 2 to 3 and updated.

Renamed Table 7.

Table 11. Document revision history (continued)

Date

Revision

Changes

AN2867 Datasheet(PDF) 40 Page - STMicroelectronics