STM32WL33C8 datasheet(62/91 Pages) STMICROELECTRONICS

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Table 49. HSE oscillator characteristics

Symbol

Parameter

Conditions

Min.

Typ.

Max.

Unit

CHSE

OSCIN OSCOUT

internal capacitor

6.7(1)

10.6(2)

14.33(3)

CHSEstep

OSCIN OSCOUT

internal capacitor

granularity 1-bit value

VBAT = 3.3 V

27 °C,

XOTUNE code between 32 and 33

0.12

HSE start-

up time

Startup time for

amplitude stabilization

From HSE enable to amplitude

ready

155

µs

Programmable trans-

conductance of the

oscillator at start-up

ISTARTUP = 00

5.1

ISTARTUP = 01

10.2

ISTARTUP = 10

20.4

1. XOTUNE programmed at minimum code = 0

2. XOTUNE programmed at center code = 32

3. XOTUNE programmed at maximum code = 63

6.3.11

Low speed external clock

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

information provided in this section is based on design simulation results obtained with typical external

components specified in the table below. In the application, the resonator and the load capacitors have to be

placed as close as possible to the oscillator pins to minimize output distortion and startup stabilization time.

Refer to the crystal resonator manufacturer for more details on the resonator characteristics (frequency, package,

accuracy).

Table 50. Low-speed external user clock characteristics(1)

Symbol

Parameter

Conditions

Min Typ Max

Unit

IDD(LSE)

LSE current consumption

LSEDRV[1:0] =00 - Low drive capability

250

LSEDRV[1:0] =01 - Medium-low drive capability

315

LSEDRV[1:0] =10 - Medium-high drive capability

500

LSEDRV[1:0] =11 - High drive capability

630

Gmcritmax

Maximum critical crystal gm

LSEDRV[1:0] =00 - low drive capability

0.50

µA/V

LSEDRV[1:0] =01 - medium-low drive capability

0.75

LSEDRV[1:0] =10 - medium-high drive capability

1.70

LSEDRV[1:0] =11 - high drive capability

2.70

tSU(LSE)(2)

Startup time

VDD stabilized

1. Guaranteed by design - not tested in production

2. tSU(LSE) is the startup time measured from the moment it is enabled (by software) until a stable 32.768 kHz oscillation is

reached. This value is measured for a standard crystal and it can vary significantly with the crystal manufacturer.

For more information onthe crystal selection, refer to application note Oscillator design guide for STM8AF/AL/S,

STM32 MCUs and MPUs (AN2867).

STM32WL33xx

Electrical characteristics

DS14221 - Rev 5

page 62/91

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