39.5.10 ADC Specifications

Table 39-26. ADC Accuracy Specifications
Operating Conditions: V_DD = V_DDIO2 = 3.0V T_A = 25ºC
Symbol	Description	Min.	Typ.	Max.	Units	Conditions
N_R	Resolution	—	—	12	bit
E_INL	Integral Non-Linearity error	—	0.1	—	LSb
E_DNL	Differential Non-Linearity error	—	0.1	—	LSb
E_OFF	Offset error	—	1.25	—	LSb
E_GAIN	Gain error	—	2.5	—	LSb
E_ABS	Absolute error	—	4	—	LSb
V_ADCREF	ADC reference voltage	1.8	—	V_DD	V
V_AIN	ADC input pin voltage	GND	—	V_ADCREF	V
Z_AIN	Recommended impedance of analog voltage source	—	—	10	kΩ
R_IN	ADC input resistance	—	14	—	kΩ
R_VREFA	ADC voltage reference ladder impedance⁽²⁾	—	50	—	kΩ
Note: The ADC conversion result never decreases with an increase in the input and has no missing codes. This is the impedance seen by the VREFA pin when the external reference is selected.

Table 39-27. ADC Conversion Timing Specifications
Symbol	Description	Min.	Typ.	Max.	Units
T_{CLK_ADC}	ADC clock period	0.5	—	8	μs
t_CNV	Conversion time	—	13.5×T_{CLK_ADC}+2×T_{CLK_PER}	—	μs
t_ACQ	Acquisition time	—	2×T_{CLK_ADC}	—	μs
f_ADC	Sample rate	8	—	130	ksps
t_S	Sampling time	—	2×T_{CLK_ADC}	—	μs
t_WARMUP	ADC warmup time	—	2	6	μs

AVR64DB28/32/48/64