124
8126F–AVR–05/12
ATtiny13A
19. Typical Characteristics
The data contained in this section is largely based on simulations and characterization of similar
devices in the same process and design methods. Thus, the data should be treated as indica-
tions of how the part will behave.
The following charts show typical behavior. These figures are not tested during manufacturing.
During characterisation devices are operated at frequencies higher than test limits but they are
not guaranteed to function properly at frequencies higher than the ordering code indicates.
All current consumption measurements are performed with all I/O pins configured as inputs and
with internal pull-ups enabled. Current consumption is a function of several factors such as oper-
ating voltage, operating frequency, loading of I/O pins, switching rate of I/O pins, code executed
and ambient temperature. The dominating factors are operating voltage and frequency.
A sine wave generator with rail-to-rail output is used as clock source but current consumption in
Power-Down mode is independent of clock selection. The difference between current consump-
tion in Power-Down mode with Watchdog Timer enabled and Power-Down mode with Watchdog
Timer disabled represents the differential current drawn by the Watchdog Timer.
The current drawn from pins with a capacitive load may be estimated (for one pin) as follows:
where V
CC
= operating voltage, C
L
= load capacitance and f
SW
= average switching frequency of
I/O pin.
19.1
Supply Current of I/O Modules
Using
, the typical characteristics of this section and the equation given one can cal-
culate the additional current consumption for peripheral modules in active and idle mode.
Peripheral modules are enabled and disabled via control bits in the Power Reduction Register.
See
“Power Reduction Register” on page 31
for details.
19.1.1
Example
Estimate current consumption in idle mode, with Timer/Counter0 and ADC enabled, the device
running at 2V and with 1MHz external clock.
From
CC
= 0.03 mA. Using
we find ADC supply current I
ADC
= 0.18 mA, and using
we find
Timer/Counter0 supply current I
TC0
= 0.004 mA. The total current consumption in idle mode is
therefore I
CCTOT
= 0.214 mA, approximately 0.21 mA.
I
CP
V
CC
C
L
f
×
×
SW
≈
Table 19-1.
Additional Current Consumption (Absolute) for Peripherals
PRR bit
Typical numbers
V
CC
= 2V, f = 1MHz
V
CC
= 3V, f = 4MHz
V
CC
= 5V, f = 8MHz
PRTIM0
4 µA
25 µA
115 µA
PRADC
180 µA
260 µA
460 µA