Electrical characteristics
Figure 37. Typical connection diagram using the ADC
STM32F103x8, STM32F103xB
V
DD
STM32F103xx
Sample and hold ADC
V
0.6 V
T
converter
(1)
(1)
AIN
R
R
ADC
AINx
12-bit
converter
I
1 µA
L
C
V
T
parasitic
V
AIN
0.6 V
(1)
C
ADC
ai14150c
1. Refer to Table 45 for the values of RAIN, RADC and CADC
.
2. Cparasitic represents the capacitance of the PCB (dependent on soldering and PCB layout quality) plus the
pad capacitance (roughly 7 pF). A high Cparasitic value will downgrade conversion accuracy. To remedy
this, fADC should be reduced.
General PCB design guidelines
Power supply decoupling should be performed as shown in Figure 38 or Figure 39,
depending on whether V
is connected to V
or not. The 10 nF capacitors should be
REF+
DDA
ceramic (good quality). They should be placed them as close as possible to the chip.
Figure 38. Power supply and reference decoupling (V not connected to V
)
DDA
REF+
STM32F103xx
V
REF+
(see note 1)
1 µF // 10 nF
V
DDA
SSA
1 µF // 10 nF
V
/V
REF–
(see note 1)
ai14388b
1. VREF+ and VREF– inputs are available only on 100-pin packages.
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Doc ID 13587 Rev 12
STMICROELECTRONICS [ ST ]
