ATmega808/809/1608/1609

32.16.2 External Reference Characteristics

Operating conditions:

V_DD = 1.8 to 5.5V
Temperature = -40°C to 125°C
DUTYCYC = 25%
CLK_ADC = 13 * f_ADC
SAMPCAP is 5 pF

The accuracy characteristics numbers are based on the characterization of the following input reference levels and V_DD ranges:

V_REF = 1.8V, V_DD = 1.8 to 5.5V
V_REF = 2.6V, V_DD = 2.7 to 5.5V
V_REF = 4.096V, V_DD = 4.5 to 5.5V
V_REF = 4.3V, V_DD = 4.5 to 5.5V

Table 32-28. ADC Accuracy Characteristics External Reference⁽²⁾
Symbol	Description	Conditions		Min.	Typ.	Max.	Unit
Res	Resolution			-	10	-	bit
INL	Integral Non-linearity		f_ADC = 15 ksps	-	0.9	3.5	LSB
			f_ADC = 77 ksps	-	0.9	3.5
			f_ADC = 115 ksps	-	1.2	3.5
DNL⁽¹⁾	Differential Non-linearity		f_ADC = 15 ksps	-	0.2	1.0	LSB
			f_ADC = 77 ksps	-	0.4	1.0
			f_ADC = 115 ksps	-	0.8	2.0
EABS	Absolute accuracy		f_ADC = 15 ksps	-	2	5	LSB
			f_ADC = 77 ksps	-	2	5
			f_ADC = 115 ksps	-	2	5
EGAIN	Gain error		f_ADC = 15 ksps	-1	2	4	LSB
			f_ADC = 77 ksps	-1	2	4
			f_ADC = 115 ksps	-1	2	4
EOFF	Offset error			-4	-0.5	2	LSB

Note:

A DNL error of less than or equal to 1 LSB ensures a monotonic transfer function with no missing codes.
These parameters are for design guidance only. Not production tested.

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