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CD00237391 Datasheet, PDF (117/177 Pages) STMicroelectronics – ARM-based 32-bit MCU, 150DMIPs, up to 1 MB Flash/128+4KB RAM
◁
STM32F20xxx
Electrical characteristics
Note:
a
Table 65.
Symbol
ADC accuracy (1)
Parameter
Test conditions
Typ Max(2) Unit
ET Total unadjusted error
EO Offset error
EG Gain error
ED Differential linearity error
EL Integral linearity error
fPCLK2 = 60 MHz,
fADC = 30 MHz, RAIN < 10 kΩ,
VDDA = 1.8(3) to 3.6 V
±2
±1.5
±1.5
±1
±1.5
±5
±2.5
±3
LSB
±2
±3
1. Better performance could be achieved in restricted VDD, frequency and temperature ranges.
2. Based on characterization, not tested in production.
3. If IRROFF is set to VDD, this value can be lowered to 1.7 V when the device operates in the 0 to 70 °C
temperature range.
ADC accuracy vs. negative injection current: injecting a negative current on any 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 analog pins which may potentially inject negative currents.
Any positive injection current within the limits specified for IINJ(PIN) and ΣIINJ(PIN) in
Section 5.3.16 does not affect the ADC accuracy.
Figure 49. ADC accuracy characteristics
4095
4094
4093
7
6
5
4
3
2
1
[1LSBIDEAL
=VREF+
4096
(or
VDDA depending
4096
on
package)]
EG
(2)
ET
(3)
(1)
EO
EL
ED
1L SBIDEAL
0
1 2 3 456
VSSA
7
4093 4094 4095 4096
VDDA
ai14395c
1. Example of an actual transfer curve.
2. Ideal transfer curve.
3. End point correlation line.
4. ET = Total Unadjusted Error: maximum deviation between the actual and the ideal transfer curves.
EO = Offset Error: deviation between the first actual transition and the first ideal one.
EG = Gain Error: deviation between the last ideal transition and the last actual one.
ED = Differential Linearity Error: maximum deviation between actual steps and the ideal one.
EL = Integral Linearity Error: maximum deviation between any actual transition and the end point
correlation line.
Doc ID 15818 Rev 9
117/177
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