STM32F217RGT7 데이터 시트보기 (PDF) - STMicroelectronics

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STM32F217RGT7

ARM-based 32-bit MCU, 150DMIPs, up to 1 MB Flash/128+4KB RAM, crypto, USB OTG HS/FS, Ethernet, 17 TIMs, 3 ADCs, 15 comm. interfaces & camera

STMicroelectronics 

Electrical characteristics

STM32F21xxx

Note:

Table 27. HSE 4-26 MHz oscillator characteristics(1) (2)

Symbol

Parameter

Conditions

Min Typ Max Unit

fOSC_IN Oscillator frequency

4

-

26 MHz

RF Feedback resistor

- 200 -

kΩ

IDD HSE current consumption

VDD=3.3 V,

ESR= 30 Ω,

- 449 -

CL=5 pF@25 MHz

µA

VDD=3.3 V,

ESR= 30 Ω,

- 532 -

CL=10 pF@25 MHz

gm Oscillator transconductance

tSU(HSE(3) Startup time

Startup

5

-

- mA/V

VDD is stabilized

-

2

- ms

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

2. Based on characterization, not tested in production.

3. 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

For CL1 and CL2, it is recommended to use high-quality external ceramic capacitors in the

5 pF to 25 pF range (typ.), designed for high-frequency applications, and selected to match

the requirements of the crystal or resonator (see Figure 29). 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.

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 29. Typical application with an 8 MHz crystal

Resonator with

integrated capacitors

CL1

8 MH z

resonator

OSC_IN

RF

Bias

controlled

gain

CL2

REXT(1)

OSC_OU T

fHS E

STM32F

ai17530

1. REXT value depends on the crystal characteristics.

Low-speed external clock generated from a crystal/ceramic resonator

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

resonator oscillator. All the information given in this paragraph are based on characterization

results obtained with typical external components specified in Table 28. In the application,

the resonator and the load capacitors have to be placed as close as possible to the oscillator

pins in order to minimize output distortion and startup stabilization time. Refer to the crystal

resonator manufacturer for more details on the resonator characteristics (frequency,

package, accuracy).

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Doc ID 17050 Rev 8

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