
317
4317K–AVR–03/2013
AT90PWM2/3/2B/3B
It is possible to calculate the typical current consumption based on the numbers from
Table 27-2for other V
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- , 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
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
Additional Current consumption
compared to Idle with external clock
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
0.085
0.043
0.053
0.156
0.105
+
++++
+
12.2mA