154
7598H–AVR–07/09
ATtiny25/45/85
22.5
Calibrated RC Oscillator Accuracy
23. Typical Characteristics
The data contained in this section is extracted from preliminary silicon characterization and will
be updated upon final characterization.
The following charts show typical behavior. These figures are not tested during manufacturing.
All current consumption measurements are performed with all I/O pins configured as inputs and
with internal pull-ups enabled. A sine wave generator with railtorail output is used as clock
source.
The power consumption in Power-down mode is independent of clock selection.
The current consumption is a function of several factors such as: operating voltage, operating
frequency, loading of I/O pins, switching rate of I/O pins, code executed and ambient tempera-
ture. The dominating factors are operating voltage and frequency.
The current drawn from capacitive loaded pins may be estimated (for one pin) as CL*VCC*f
where CL = load capacitance, VCC = operating voltage and f = average switching frequency of
I/O pin.
The parts are characterized at frequencies higher than test limits. Parts are not guaranteed to
function properly at frequencies higher than the ordering code indicates.
The difference between current consumption in Power-down mode with Watchdog Timer
enabled and Power-down mode with Watchdog Timer disabled represents the differential cur-
rent drawn by the Watchdog Timer.
Table 22-4.
Calibration Accuracy of Internal RC Oscillator
Frequency
Vcc
Temperature
Calibration
Accuracy
Factory
Calibration
8.0 MHz
3V
25°C
±1%
User Calibration
7.3 - 8.1 MHz
2.7V - 5.5V
-40°C - +125°C
±14%
