STM32L151CCH7DTR View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

STM32L151CCH7DTR

Ultra-low-power 32-bit MCU ARM®-based Cortex®-M3, 256KB Flash, 32KB SRAM, 8KB EEPROM, LCD, USB, ADC, DAC

STMicroelectronics 

STM32L151xC STM32L152xC

Electrical characteristics

Figure 17. HSE oscillator circuit diagram

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1. REXT value depends on the crystal characteristics.

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

DLE

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 30. 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).

Symbol

Table 30. LSE oscillator characteristics (fLSE = 32.768 kHz)(1)

Parameter

Conditions

Min Typ Max Unit

fLSE

Low speed external oscillator

frequency

-

- 32.768 - kHz

RF Feedback resistor

-

-

Recommended load capacitance

C(2) versus equivalent serial

resistance of the crystal (RS)(3)

RS = 30 kΩ

-

ILSE LSE driving current

VDD = 3.3 V, VIN = VSS -

IDD (LSE)

LSE oscillator current

consumption

VDD = 1.8 V

-

VDD = 3.0 V

-

VDD = 3.6V

-

gm Oscillator transconductance

tSU(LSE)(4) Startup time

-

3

VDD is stabilized

-

1.2

- MΩ

8

-

pF

-

1.1 µA

450

-

600

-

nA

750

-

-

- µA/V

1

-

s

1. Guaranteed by characterization results.

2. Refer to the note and caution paragraphs below the table, and to the application note AN2867 “Oscillator

design guide for ST microcontrollers”.

3. The oscillator selection can be optimized in terms of supply current using an high quality resonator with

small RS value for example MSIV-TIN32.768kHz. Refer to crystal manufacturer for more details.

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