ATtiny3224/3226/3227

33.15 VREF

Table 33-21. Internal Voltage Reference Characteristics⁽¹⁾
Symbol	Description	Min.	Typ.	Max.	Unit
t_start	Start-up time	-	25	-	µs
V_DD	Power supply voltage range for 1V024	1.8	-	5.5	V
	Power supply voltage range for 2V048	2.6	-	5.5
	Power supply voltage range for 2V500	3.0	-	5.5
	Power supply voltage range for 4V096	4.6	-	5.5

Note:

These parameters are for design guidance only and are not production tested.

Table 33-22. ADC Internal Voltage Reference Characteristics⁽¹⁾
Symbol⁽²⁾	Description	Condition	Min.	Typ.	Max.	Unit
2V048	Internal reference voltage	V_DD = [1.8, 5.5]V T = [0, 85]°C	-2.0		2.0	%
1V024 2V500 4V096	Internal reference voltage	V_DD = [1.8, 5.5]V T = [0, 85]°C	-3.0		3.0
1V024 2V048 2V500 4V096	Internal reference voltage	V_DD = [1.8, 5.5]V T = [-40, 125]°C	-5.0		5.0

Note:

These values are based on characterization and not covered by production test limits.
The symbols xVxxx refer to the respective values of the REFSEL bit field in the ADC0.CTRLC register.

Table 33-23. AC Internal Voltage Reference Characteristics⁽¹⁾
Symbol⁽²⁾	Description	Condition	Min.	Typ.	Max.	Unit
1V024 2V048 2V500 4V096	Internal reference voltage	V_DD = [1.8, 5.5]V T = [-40, 125]°C	-4.5		4.5	%

Note:

These values are based on characterization and not covered by production test limits.
The symbols xVxxx refer to the respective values of the AC0REFSEL bit field in the VREF.CTRLA register.

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