Datasheet

917
32142D–06/2013
ATUC64/128/256L3/4U
( ) of the PCB and source must be taken into account when calculating the required
sample and hold time. Figure 35-8 shows the ADC input channel equivalent circuit.
Figure 35-8. ADC Input
The minimum sample and hold time (in ns) can be found using this formula:
Where n is the number of bits in the conversion. is defined by the SHTIM field in the
ADCIFB ACR register. Please refer to the ADCIFB chapter for more information.
35.9.6.2 Applicable Conditions and Derating Data
Note: 1. These values are based on simulation and characterization of other AVR microcontrollers manufactured in the same pro-
cess technology. These values are not covered by test limits in production.
C
SOURCE
ADCVREFP/2
C
ONCHIP
R
ONCHIP
Positive Input
R
SOURCE
C
SOURCE
V
IN
t
SAMPLEHOLD
R
ONCHIP
R+
SOURCE
C
ONCHIP
C
SOURCE
+ 2
n 1+
ln
t
SAMPLEHOLD
Table 35-31. Transfer Characteristics 12-bit Resolution Mode
(1)
Parameter Conditions Min Typ Max Units
Resolution 12 Bit
Integral non-linearity
ADC clock frequency = 6MHz,
Input Voltage Range = 0 - V
ADVREFP
+/-4
LSB
ADC clock frequency = 6MHz,
Input Voltage Range = (10% V
ADVREFP
) -
(90% V
ADVREFP
)
+/-2
Differential non-linearity
ADC clock frequency = 6MHz
-1.5 1.5
Offset error +/-3
Gain error +/-5
Table 35-32. Transfer Characteristics, 10-bit Resolution Mode
(1)
Parameter Conditions Min Typ Max Units
Resolution 10 Bit
Integral non-linearity
ADC clock frequency = 6MHz
+/-1
LSB
Differential non-linearity -1.0 1.0
Offset error +/-1
Gain error +/-2