STM32F103xx
Electrical characteristics
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R
AIN
External input impedance
TBD
(2)(3)
k
Ω
C
AIN
External capacitor on analog
input
pF
I
lkg
Negative input leakage current
on analog pins
V
IN
<
V
SS,
| I
IN
| < 400 µA
on adjacent analog pin
5
6
µ
A
R
ADC
Sampling switch resistance
1
k
Ω
C
ADC
Internal sample and hold
capacitor
5
pF
t
CAL
Calibration time
f
ADC
= 14MHz
5.9
µs
83
1/f
ADC
t
lat
Injection conversion latency
f
ADC
= 14 MHz
0.214
µs
3
1/f
ADC
t
S
Sampling time
f
ADC
= 14 MHz
0.107
17.1
µs
t
STAB
Power-up time
0
0
1
µs
t
CONV
Total conversion time (including
sampling time)
f
ADC
= 14 MHz
1
18
µs
14 (1.5 for sampling
+12.5 for successive
approximation)
1/f
ADC
1.
TBD = to be determined.
2.
Depending on the input signal variation (f
AIN
), C
AIN
can be increased for stabilization time and reduced to
allow the use of a larger serial resistor (R
AIN
). It is valid for all f
ADC
frequencies
≤
14 MHz.
3.
During the sample time the input capacitance C
AIN
(5 max) can be charged/discharged by the external
source. The internal resistance of the analog source must allow the capacitance to reach its final voltage
level within t
S.
After the end of the sample time t
S
, changes of the analog input voltage have no effect on
the conversion result. Values for the sample clock t
S
depend on programming.
Table 40.
ADC accuracy (f
PCLK2
= 14 MHz, f
ADC
= 14 MHz, R
AIN
<10 k
Ω
, V
DDA
=
3.3 V)
(1)
1.
TBD = to be determined.
Symbol
Parameter
Conditions
Typ
Max
Unit
|E
T
|
Total unadjusted error
(2)
2.
ADC Accuracy vs. Negative Injection Current: Injecting negative current on any of the standard (non-
robust) analog input pins should be avoided as this significantly reduces the accuracy of the conversion
being performed on another analog input. It is recommended to add a Schottky diode (pin to ground) to
standard analog pins which may potentially inject negative current.
Any positive injection current within the limits specified for I
INJ(PIN)
and
Σ
I
INJ(PIN)
affect the ADC accuracy.
3
TBD
LSB
|E
O
|
Offset error
(2)
1
TBD
|E
G
|
Gain Error
(2)
2
TBD
|E
D
|
Differential linearity error
(2)
3
TBD
|E
L
|
Integral linearity error
(2)
2
TBD
Table 39.
ADC characteristics
(1)
(continued)
Symbol
Parameter
Conditions
Min
Typ
Max
Unit