Data Sheet

428
ATmega48A/PA/88A/PA/168A/PA/328/P [DATASHEET]
Atmel-8271H-AVR- ATmega-Datasheet_08/2014
31.5.3 ATmega168A Supply Current of IO Modules
The tables and formulas below can be used to calculate the additional current consumption for the different I/O
modules in Active and Idle mode. The enabling or disabling of the I/O modules are controlled by the Power
Reduction Register. See ”Power Reduction Register” on page 43 for details.
It is possible to calculate the typical current consumption based on the numbers from Table 31-12 on page 453
for other V
CC
and frequency settings than listed in Table 31-11 on page 453.
31.5.3.1 Example
Calculate the expected current consumption in idle mode with TIMER1, ADC, and SPI enabled at V
CC
= 2.0V
and F = 1MHz. From Table 31-12 on page 453, third column, we see that we need to add 10.3% for the
TIMER1, 20.3% for the ADC, and 17.1% for the SPI module. Reading from Figure 31-242 on page 450, we find
that the idle current consumption is ~0.027 mA at V
CC
= 2.0V and F = 1MHz. The total current consumption in
idle mode with TIMER1, ADC, and SPI enabled, gives:
Table 31-9. ATmega168A: Additional Current Consumption for the different I/O modules (absolute values)
PRR bit Typical numbers
V
CC
= 2V, F = 1MHz V
CC
= 3V, F = 4MHz V
CC
= 5V, F = 8MHz
PRUSART0 2.86µA 20.3µA 52.2µA
PRTWI 6.00µA 44.1µA 122.0µA
PRTIM2 4.97µA 33.2µA 79.8µA
PRTIM1 3.50µA 23.0µA 55.3µA
PRTIM0 1.43µA 9.2µA 21.4µA
PRSPI 5.01µA 38.6µA 111.4µA
PRADC 6.34µA 45.7µA 123.6µA
Table 31-10. ATmega168A: Additional Current Consumption (percentage) in Active and Idle mode
PRR bit
Additional Current consumption
compared to Active with external
clock (see Figure 31-237 on page
447 and Figure 31-238 on page
448)
Additional Current consumption
compared to Idle with external
clock (see Figure 31-242 on page
450 and Figure 31-243 on page
450)
PRUSART0 1.5% 8.9%
PRTWI 3.2% 19.5%
PRTIM2 2.4% 14.8%
PRTIM1 1.7% 10.3%
PRTIM0 0.7% 4.1%
PRSPI 2.9% 17.1%
PRADC 3.4% 20.3%
ICCtotal 0.027 mA (1 + 0.103 + 0.203 + 0.171) 0.040 mA