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.
Table 29-5. ATmega168PA: Additional Current Consumption for the different I/O modules
(absolute values)
PRR bit
Typical numbers
VCC = 2V, F = 1 MHz
2.86 uA
VCC = 3V, F = 4 MHz
20.3 uA
VCC = 5V, F = 8 MHz
52.2 uA
PRUSART0
PRTWI
6.00 uA
44.1uA
122.0 uA
PRTIM2
PRTIM1
PRTIM0
PRSPI
4.97 uA
33.2 uA
79.8 uA
3.50 uA
23.0 uA
55.3 uA
1.43 uA
9.2 uA
21.4 uA
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
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)
PRR bit
PRUSART0
PRTWI
1.5%
3.2%
2.4%
1.7%
0.7%
2.9%
3.4%
8.9%
19.5%
14.8%
10.3%
4.1%
PRTIM2
PRTIM1
PRTIM0
PRSPI
17.1%
20.3%
PRADC
It is possible to calculate the typical current consumption based on the numbers from Table 29-6
on page 380 for other VCC 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 VCC = 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 VCC = 2.0V
and F = 1MHz. The total current consumption in idle mode with TIMER1, ADC, and SPI enabled,
gives:
ICCtotal ≈ 0.027 mA ⋅ (1 + 0.103 + 0.203 + 0.171) ≈ 0.040 mA
380
8161D–AVR–10/09