ATtiny3216/3217

36.9 Oscillators and Clocks

Operating conditions:

V_DD = 3V, except where specified otherwise

Table 36-12. Internal Oscillator (OSC20M) Characteristics
Symbol	Description	Condition		Min.	Typ.	Max.	Unit
f_OSC20M	Accuracy with 16 MHz and 20 MHz frequency selection relative to the factory-stored frequency value	Factory calibrated V_DD = 3V⁽¹⁾	T = [0, 70]°C, V_DD = [1.8, 4.5]V⁽³⁾	-2.0	-	2.0	%
		Factory calibrated V_DD = 5V⁽¹⁾	T = [0, 70]°C, V_DD = [4.5, 5.5]V⁽³⁾	-2.0	-	2.0	%
	Accuracy with 16 MHz and 20 MHz frequency selection	Factory calibrated	T = 25°C, 3.0V	-3.0	-	3.0	%
			T = [0, 70]°C, V_DD = [1.8, 3.6]V⁽³⁾	-4.0	-	4.0
			Full operation range⁽³⁾	-5.0	-	5.0
f_CAL	User calibration range	OSC20M⁽²⁾ = 16 MHz		14.5	-	17.5	MHz
f_CAL	User calibration range	OSC20M⁽²⁾ = 20 MHz		18.5	-	21.5	MHz
%CAL	Calibration step size			-	1.5	-	%
DC	Duty cycle			-	50	-	%
T_Start	Start-up time	Within 2% accuracy		-	8	-	µs

Note:

See the description of OSC20M on calibration.
Oscillator frequencies above speed specification must be divided so that the CPU clock always is within specification.
These values are based on characterization and not covered by production test limits.

Table 36-13. 32.768 kHz Internal Oscillator (OSCULP32K) Characteristics
Symbol	Description	Condition		Min.	Typ.	Max.	Unit
f_OSCULP32K	Accuracy	Factory calibrated	T = 25°C, 3.0V	-3	-	3	%
			T = [0, 70]°C, V_DD = [1.8, 3.6]V⁽¹⁾	-10	-	10
			Full operation range⁽¹⁾	-30	-	30
DC	Duty cycle			-	50	-	%
T_Start	Start-up time			-	250	-	µs

Note:

These values are based on characterization and not covered by production test limits.

Table 36-14. 32.768 kHz External Crystal Oscillator (XOSC32K) Characteristics
Symbol	Description	Condition	Min.	Typ.	Max.	Unit
F_out	Frequency		-	32.768	-	kHz
T_Start	Start-up time	C_L = 7.5 pF	-	300	-	ms
C_L	Crystal load capacitance		7.5	-	12.5	pF
C_TOSC1	Parasitic capacitor load		-	5.5	-	pF
C_TOSC2	Parasitic capacitor load		-	5.5	-	pF
ESR	Equivalent Series Resistance - Safety Factor = 3	C_L = 7.5 pF	-	-	80	kΩ
ESR	Equivalent Series Resistance - Safety Factor = 3	C_L = 12.5 pF	-	-	40	kΩ

Figure 36-3. External Clock Waveform Characteristics

Table 36-15. External Clock Characteristics
Symbol	Description	Condition	V_DD = [1.8, 5.5]V		V_DD = [2.7, 5.5]V		V_DD = [4.5, 5.5]V		Unit
Symbol	Description	Condition	Min.	Max.	Min.	Max.	Min.	Max.	Unit
f_CLCL	Frequency		0	5.0	0.0	10.0	0.0	20.0	MHz
t_CLCL	Clock period		200	-	100	-	50	-	ns
t_CHCX	High time		80	-	40	-	20	-	ns
t_CLCX	Low time		80	-	40	-	20	-	ns

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