STM32F102RB STMicroelectronics, STM32F102RB Datasheet - Page 41

• Manufacturer Part Number: STM32F102RB
• Description: Mainstream USB Access line, ARM Cortex-M3 MCU with 128 Kbytes Flash, 48 MHz CPU, USB FS
• Manufacturer: STMicroelectronics

Specifications of STM32F102RB

• Core: ARM 32-bit Cortex™-M3 CPU
• Peripherals Supported: timers, ADC, SPIs, I2Cs and USARTs
• Conversion Range: 0 to 3.6 V
• Systick Timer: 24-bit downcounter

STM32F102x8, STM32F102xB
Note:
Figure 18. Typical application with an 8 MHz crystal
1. R
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
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).
Table 22.
1. Refer to the note and caution paragraphs below the table, and to the application note AN2867 “Oscillator
2. The oscillator selection can be optimized in terms of supply current using an high quality resonator with
3.
For C
15 pF range selected to match the requirements of the crystal or resonator. C
usually the same size. The crystal manufacturer typically specifies a load capacitance which
is the series combination of C
Load capacitance C
C
between 2 pF and 7 pF.
stray
t
SU(LSE)
Symbol
design guide for ST microcontrollers”.
small R
32.768 kHz oscillation is reached. This value is measured for a standard crystal resonator and it can vary
significantly with the crystal manufacturer
t
SU(LSE)
EXT
C
R
g
I
L1
(1)
2
m
is the pin capacitance and board or trace PCB-related capacitance. Typically, it is
F
value depends on the crystal characteristics.
and C
(3)
S
is the startup time measured from the moment it is enabled (by software) to a stabilized
value for example MSIV-TIN32.768 kHz. Refer to crystal manufacturer for more details
integrated capacitors
LSE oscillator characteristics (f
Feedback resistor
Recommended load capacitance
versus equivalent serial
resistance of the crystal (R
LSE driving current
Oscillator transconductance
Startup time
L2
it is recommended to use high-quality ceramic capacitors in the 5 pF to
Resonator with
L
C L2
C L1
has the following formula: C
Parameter
8 MH z
resonator
R EXT (1)
L1
Doc ID 15056 Rev 3
and C
S
L2
)
OSC_OU T
(2)
OSC_IN
.
LSE
V
R F
DD
V
Conditions
R
V
L
DD
S
= 32.768 kHz)
IN
is stabilized
= C
= 30 k
controlled
= 3.3 V
= V
Bias
gain
L1
SS
x C
L2
Table
/ (C
Electrical characteristics
Min
STM32F102xx
5
L1
22. In the application,
f HSE
+ C
Typ
5
3
L2
) + C
L1
ai14977b
Max
and C
1.4
15
stray
L2,
where
µA/V
Unit
M
41/69
pF
µA
s
are