Datasheet

DocID022691 Rev 4 75/131

STM32F37xxx Electrical characteristics

114

For C

and C

, it is recommended to use high-quality external ceramic capacitors in the

5 pF to 20 pF range (typ.), designed for high-frequency applications, and selected to match

the requirements of the crystal or resonator (see Figure 14). C

and C

are usually the

same size. The crystal manufacturer typically specifies a load capacitance which is the

series combination of C

and C

. PCB and MCU pin capacitance must be included (10 pF

can be used as a rough estimate of the combined pin and board capacitance) when sizing

and C

Note: For information on electing the crystal, refer to the application note AN2867 “Oscillator

design guide for ST microcontrollers” available from the ST website www.st.com.

Figure 14. Typical application with an 8 MHz crystal

1. R

EXT

value depends on the crystal characteristics.

MS19876V1

OSC_OU T

OSC_IN

HSE

8 MHz

resonator

EXT

(1)

Resonator with

integrated capacitors

Bias

controlled

gain