Table 57. Maximum Source Impedance Rain Max; Figure 27. Adc Accuracy Characteristics; Figure 28. Typical Connection Diagram Using The Adc - ST STM32L15 QC Series Datasheet

STM32L151xC/C-A STM32L152xC/C-A
Output code
n
2 -1
2 n -2
2 n -3
7
6
5
E
O
4
3
2
1
0
2 3
1
1. Refer to
characteristics
2. C
parasitic
pad capacitance (roughly 7 pF). A high C
f must be reduced.
ADC

Figure 27. ADC accuracy characteristics

(2)
E
T
E
L
E
D
1 LSB
IDEAL
7
4 5 6

Figure 28. Typical connection diagram using the ADC

R (1)
AINx
AIN
C parasitic
V
AIN
Table 57: Maximum source impedance R
for the value of C
ADC
represents the capacitance of the PCB (dependent on soldering and PCB layout quality) plus the
E
(1) Example of an actual transfer curve
G
(2) Ideal transfer curve
(3) End-point correlation line
n
= ADC resolution
E = total unajusted error: maximum deviation
T
between the actual and ideal transfer curves
(3)
E = offset error: maximum deviation between the
(1) O
first actual transition and the first ideal one
E = gain error: deviation between the last ideal
G
transition and the last actual one
E = differential linearity error: maximum deviation
D
between actual steps and the ideal one
E = integral linearity error: maximum deviation
L
between any actual transition and the end point
correlation line
V
n
n n 2
2 n -3 2 -2 2 -1
REF+
V
DDA
IL± 50 nA
max for the value of R
AIN
.
value downgrades conversion accuracy. To remedy this,
parasitic
DS10262 Rev 8
Electrical characteristics
(or V )
DDA
STM32Lxx
Sample and hold
ADC converter
12-bit
converter
C (1)
ADC
and Table 55: ADC
AIN
MS19880V4
ai17856e
105/134
113