Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD Data Sheet
Product codes
ATSAM4S-WPIR-RD
SAM4S Series [DATASHEET]
Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14
1156
is a computation example for the above formula, where V
ADVREF
= 3V:
44.8.4.3 Example of LSB Computation
The LSB is relative to the analog scale V
ADVREF
.
The term LSB expresses the quantization step in volts, also used for one ADC code variation.
Single-ended (SE) (ex: V
ADVREF
=3.0V)
̶
Gain = 1, LSB = (3.0V / 4096) = 732 µV
̶
Gain = 2, LSB = (1.5V / 4096) = 366 µV
̶
Gain = 4, LSB = (750 mV / 4096) = 183 µV
Differential (DIFF) (ex: V
ADVREF
=3.0V)
̶
Gain = 0.5, LSB = (6.0V / 4096) = 1465 µV
̶
Gain = 1, LSB = (3.0V / 4096) = 732 µV
̶
Gain = 2, LSB = (1.5V / 4096) = 366 µV
44.8.5 ADC Electrical Characteristics
The gain error depends on the gain value and the OFFx bit. The data are given with and without autocorrection at
27°C. The data include the ADC performances as the PGA and ADC core cannot be separated. The temperature
and voltage dependency are given as separate parameters.
44.8.5.1 Gain and Offset Errors
For:
a given gain error: E
G
(%)
a given ideal code (Ci)
a given offset error: E
O
(LSB)
the actual code (Ca) is calculated using the following formula
Table 44-42.
Input Voltage Values in Single-ended Mode, OFFx=0
Ci
Gain = 1
Gain = 2
Gain = 4
0
0
0
0
2047
1.5
0.75
0.375
4095
3
1.5
0.75
Table 44-43.
Voltage and Temperature Dependencies
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
T
GK
Gain Temperature dependency
-40°C to 105°C
—
—
5
ppm/°C
V
GK
Gain Supply dependency
VDDIN
—
—
0.025
%/V
T
OK
Offset Temperature dependency
-40°C to 105°C
—
—
5
ppm/°C
V
OK
Offset Supply dependency
VDDIN
—
—
0.025
%/V
Ca
1
E
G
100
---------
+
C
i
2047
–
(
)
×
2047
E
O
+
+
=