Datasheet

129
XMEGA A4U [DATASHEET]
Atmel-8387H-AVR-ATxmega16A4U-34A4U-64A4U-128A4U-Datasheet_09/2014
36.3.14.4 32kHz Internal ULP Oscillator characteristics
Table 36-89. 32kHz internal ULP oscillator characteristics.
36.3.14.5 Internal Phase Locked Loop (PLL) characteristics
Table 36-90. Internal PLL characteristics.
Note: 1. The maximum output frequency vs. supply voltage is linear between 1.8V and 2.7V, and can never be higher than four times the maximum CPU frequency.
36.3.14.6 External clock characteristics
Figure 36-17. External clock drive waveform
Table 36-91. External clock used as system clock without prescaling.
Symbol Parameter Condition Min. Typ. Max. Units
Factory calibrated frequency 32 kHz
Factory calibrated accuracy T = 85°C, V
CC
= 3.0V -12 12 %
Accuracy -30 30 %
Symbo
l Parameter Condition Min. Typ. Max. Units
f
IN
Input frequency Output frequency must be within f
OUT
0.4 64 MHz
f
OUT
Output frequency
(1)
V
CC
= 1.6 - 1.8V 20 48
MHz
V
CC
= 2.7 - 3.6V 20 128
Start-up time 25 µs
Re-lock time 25 µs
t
CH
t
CL
t
CK
t
CH
V
IL1
V
IH1
t
CR
t
CF
Symbol Parameter Condition Min. Typ. Max. Units
1/t
CK
Clock Frequency
(1)
V
CC
= 1.6 - 1.8V 0 12
MHz
V
CC
= 2.7 - 3.6V 0 32
t
CK
Clock Period
V
CC
= 1.6 - 1.8V 83.3
ns
V
CC
= 2.7 - 3.6V 31.5
t
CH
Clock High Time
V
CC
= 1.6 - 1.8V 30.0
ns
V
CC
= 2.7 - 3.6V 12.5