STM32L152R8(2013) View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

STM32L152R8
(Rev.:2013)

Ultra-low-power 32-bit MCU ARM®-based Cortex®-M3, 128KB Flash, 16KB SRAM, 4KB EEPROM, LCD, USB, ADC, DAC

STMicroelectronics 

Electrical characteristics

STM32L151x6/8/B, STM32L152x6/8/B

Note:

Caution:

For CL1 and CL2, it is recommended to use high-quality ceramic capacitors in the 5 pF to

15 pF range 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.

Load capacitance CL has the following formula: CL = CL1 x CL2 / (CL1 + CL2) + Cstray where

Cstray is the pin capacitance and board or trace PCB-related capacitance. Typically, it is

between 2 pF and 7 pF.

To avoid exceeding the maximum value of CL1 and CL2 (15 pF) it is strongly recommended

to use a resonator with a load capacitance CL ≤ 7 pF. Never use a resonator with a load

capacitance of 12.5 pF.

Example: if you choose a resonator with a load capacitance of CL = 6 pF and Cstray = 2 pF,

then CL1 = CL2 = 8 pF.

Figure 17. Typical application with a 32.768 kHz crystal

Resonator with

integrated capacitors

CL1

32.768 kH z

resonator

CL2

OSC32_IN

RF

OSC32_OU T

Bias

controlled

gain

fLSE

STM32L15xxx

ai17853

70/121

Doc ID 17659 Rev 8

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