Datasheet

317
4317K–AVR–03/2013
AT90PWM2/3/2B/3B
It is possible to calculate the typical current consumption based on the numbers from Table 27-2
for other V
CC
and frequency settings than listed in Table 27-1.
27.2.1.1 Example 1
Calculate the expected current consumption in idle mode with USART, TIMER1, and SPI
enabled at V
CC
= 3.0V and F = 1MHz. From Table 27-2, third column, we see that we need to
add 18% for the USART, 26% for the SPI, and 11% for the TIMER1 module. Reading from
Fig-
ure 27-5, we find that the idle current consumption is ~0,17mA at V
CC
= 3.0V and F = 1MHz. The
total current consumption in idle mode with USART0, TIMER1, and SPI enabled, gives:
27.2.1.2 Example 2
Same conditions as in example 1, but in active mode instead. From Table 27-2, second column
we see that we need to add 3.3% for the USART, 4.8% for the SPI, and 2.0% for the TIMER1
module. Reading from
Figure 27-1, we find that the active current consumption is ~0,6mA at V
CC
= 3.0V and F = 1MHz. The total current consumption in idle mode with USART, TIMER1, and
SPI enabled, gives:
27.2.1.3 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 ~ 7.0mA (from
Figure 27-2). Then, by using the numbers from Table 27-2 - second column,
we find the total current consumption:
Table 27-2. Additional Current Consumption (percentage) in Active and Idle mode
PRR bit
Additional Current consumption
compared to Active with external
clock
(see Figure 27-1 and Figure 27-2)
Additional Current consumption
compared to Idle with external clock
(see Figure 27-5 and Figure 27-6)
PRPSC2 10% 25%
PRPSC1 10% 25%
PRPSC0 10% 25%
PRTIM1 8.5% 22%
PRTIM0 4.3% 11%
PRSPI 5.3% 14%
PRUSART 15.6 36
PRADC 10.5% 25%
ICCtotal 0.17mA 10.360.220.14+++ 0.29mA
ICCtotal 0.6mA 1 0.156 0.085 0.053+++ 0.77mA
CCtotal 7.0mA 1 0.1 0.1 0.1 0.085 0.043 0.053 0.156 0.105++++++++ 12.2mA