Datasheet
ATmega48A/PA/88A/PA/168A/PA/328/P
2018 Microchip Technology Inc. Data Sheet Complete DS40002061A-page 332
31.1.3 ATmega48A: 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 51 for details.
It is possible to calculate the typical current consumption based on the numbers from Table 31-2 on page 332
for other V
CC
and frequency settings than listed in Table 31-1 on page 332.
31.1.3.1 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 31-4 on page 357, third column, we see that we need to add 11.2% for the TIMER1,
22.1% for the ADC, and 17.6% for the SPI module. Reading from
Figure 31-53 on page 354, we find that the idle
current consumption is ~0.028 mA at V
CC
= 2.0V and F = 1MHz. The total current consumption in idle mode with
TIMER1, ADC, and SPI enabled, gives:
Table 31-1. ATmega48PA: 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 2.9uA 20.7µA 97.4µA
PRTWI 6.0µA 44.8µA 219.7µA
PRTIM2 5.0µA 34.5µA 141.3µAµA
PRTIM1 3.6µA 24.4µA 107.7µA
PRTIM0 1.4µA 9.5µA 38.4µA
PRSPI 5.0µA 38.0µA 190.4µA
PRADC 6.1µA 47.4µA 244.7µA
Table 31-2. ATmega48PA: Additional Current Consumption (percentage) in Active and Idle mode
PRR bit
Additional Current consumption
compared to Active with external
clock (see Figure 31-48 on page
352 and Figure 31-49 on page
352)
Additional Current consumption
compared to Idle with external
clock (see Figure 31-53 on page
354 and Figure 31-54 on page
355)
PRUSART0 1.8% 11.4%
PRTWI 3.9% 20.6%
PRTIM2 2.9% 15.7%
PRTIM1 2.1% 11.2%
PRTIM0 0.8% 4.2%
PRSPI 3.3% 17.6%
PRADC 4.2% 22.1%
ICCtotal 0.028 mA (1 + 0.112 + 0.221 + 0.176) 0.042 mA