Data Sheet

380
8161D–AVR–10/09
ATmega48PA/88PA/168PA/328P
29.3.3 ATmega168PA 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 42 for
details.
It is possible to calculate the typical current consumption based on the numbers from Table 29-6
on page 380 for other V
CC
and frequency settings than listed in Table 29-5 on page 380.
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 29-6 on page 380, 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 29-98 on page 377, 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 29-5. ATmega168PA: Additional Current Consumption for the different I/O modules
(absolute values)
PRR bit Typical numbers
V
CC
= 2V, F = 1 MHz V
CC
= 3V, F = 4 MHz V
CC
= 5V, F = 8 MHz
PRUSART0 2.86 uA 20.3 uA 52.2 uA
PRTWI 6.00 uA 44.1uA 122.0 uA
PRTIM2 4.97 uA 33.2 uA 79.8 uA
PRTIM1 3.50 uA 23.0 uA 55.3 uA
PRTIM0 1.43 uA 9.2 uA 21.4 uA
PRSPI 5.01 uA 38.6 uA 111.4 uA
PRADC 6.34 uA 45.7 uA 123.6 uA
Table 29-6. ATmega168PA: Additional Current Consumption (percentage) in Active and Idle
mode
PRR bit
Additional Current consumption
compared to Active with external
clock (see Figure 29-93 on page
375 and Figure 29-94 on page
375)
Additional Current consumption
compared to Idle with external
clock (see Figure 29-98 on page
377 and Figure 29-99 on page
378)
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≈≈