ATMEGA48V_09 Datasheet, PDF (321/378 Pages) ATMEL Corporation – 8-bit Microcontroller with 8K Bytes In-System Programmable Flash

ATmega48/88/168
29.3.0.1
29.3.0.2
29.3.0.3
Table 29-2. Additional Current Consumption (percentage) in Active and Idle mode
PRR bit
Additional Current consumption
compared to Active with external
clock
(see Figure 29-1 and Figure 29-2)
Additional Current consumption
compared to Idle with external clock
(see Figure 29-7 and Figure 29-8)
PRUSART0
3.3%
18%
PRTWI
4.8%
26%
PRTIM2
4.7%
25%
PRTIM1
2.0%
11%
PRTIM0
1.6%
8.5%
PRSPI
6.1%
33%
PRADC
4.9%
26%
It is possible to calculate the typical current consumption based on the numbers from Table 2 for
other V_CC and frequency settings than listed in Table 1.
Example 1
Calculate the expected current consumption in idle mode with USART0, TIMER1, and TWI
enabled at V_CC = 3.0V and F = 1MHz. From Table 2, third column, we see that we need to add
18% for the USART0, 26% for the TWI, and 11% for the TIMER1 module. Reading from Figure
3, we find that the idle current consumption is ~0,075mA at V_CC = 3.0V and F = 1MHz. The total
current consumption in idle mode with USART0, TIMER1, and TWI enabled, gives:
ICCtotal ≈ 0,075mA • (1 + 0,18 + 0,26 + 0,11) ≈ 0,116mA
Example 2
Same conditions as in example 1, but in active mode instead. From Table 2, second column we
see that we need to add 3.3% for the USART0, 4.8% for the TWI, and 2.0% for the TIMER1
module. Reading from Figure 1, we find that the active current consumption is ~0,42mA at V_CC =
3.0V and F = 1MHz. The total current consumption in idle mode with USART0, TIMER1, and
TWI enabled, gives:
ICCtotal ≈ 0,42mA • (1 + 0,033 + 0,048 + 0,02) ≈ 0,46mA
Example 3
All I/O modules should be enabled. Calculate the expected current consumption in active mode
at V_CC = 3.6V and F = 10MHz. We find the active current consumption without the I/O modules
to be ~ 4.0mA (from Figure 2). Then, by using the numbers from Table 2 - second column, we
find the total current consumption:
ICCtotal ≈ 4,0mA • (1 + 0,033 + 0,048 + 0,047 + 0,02 + 0,016 + 0,061 + 0,049) ≈ 5,1mA
2545R–AVR–07/09
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