ATtiny25 datasheet(154/196 Pages) ATMEL

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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

25°C

±1%

User Calibration

7.3 - 8.1 MHz

2.7V - 5.5V

-40°C - +125°C

±14%

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