STM32F030X4 datasheet(54/93 Pages) STMICROELECTRONICS

54 / 93 page

Electrical characteristics

STM32F030x4/x6/x8/xC

54/93

DS9773 Rev 4

For CL1 and CL2, 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 17). CL1 and CL2 are usually the

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

series combination of CL1 and CL2. 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

CL1 and CL2.

Note:

For information on selecting the crystal, refer to the application note AN2867 “Oscillator

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

Figure 17. Typical application with an 8 MHz crystal

1. REXT value depends on the crystal characteristics.

Low-speed external clock generated from a crystal resonator

The low-speed external (LSE) clock can be supplied with a 32.768 kHz crystal resonator

oscillator. All the information given in this paragraph are based on design simulation results

IDD

HSE current consumption

During startup(3)

8.5

VDD = 3.3 V,

Rm = 45

Ω,

CL = 10 pF@8 MHz

-0.5

VDD = 3.3 V,

Rm = 30

Ω,

CL = 20 pF@32 MHz

-1.5

Oscillator transconductance

Startup

mA/V

tSU(HSE)(4) Startup time

VDD is stabilized

1. Resonator characteristics given by the crystal/ceramic resonator manufacturer.

2. Guaranteed by design, not tested in production.

3. This consumption level occurs during the first 2/3 of the tSU(HSE) startup time

4. tSU(HSE) is the startup time measured from the moment it is enabled (by software) to a stabilized 8 MHz

oscillation is reached. This value is measured for a standard crystal resonator and it can vary significantly

with the crystal manufacturer

Table 33. HSE oscillator characteristics

Symbol

Parameter

Conditions(1)

Min(2)

Typ

Max(2)

Unit

MS19876V1

(1)

OSC_IN

OSC_OUT

Bias

controlled

gain

fHSE

REXT

8 MHz

resonator

Resonator with integrated

capacitors

CL1

CL2

STM32F030X4 Datasheet(PDF) 54 Page - STMicroelectronics

STM32F030X4 Datasheet(HTML) 54 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93

Datasheet Download

Link URL