Datasheet

Table Of Contents
Electrical characteristics STM32F405xx, STM32F407xx
94/202 DocID022152 Rev 8
floating pins, they must either be configured in analog mode, or forced internally to a definite
digital value. This can be done either by using pull-up/down resistors or by configuring the
pins in output mode.
I/O dynamic current consumption
In addition to the internal peripheral current consumption measured previously (see
Table 28: Peripheral current consumption), the I/Os used by an application also contribute
to the current consumption. When an I/O pin switch
es, it uses the current from the MCU
supply voltage to supply the I/O pin circuitry and to charge/discharge the capacitive load
(internal or external) connected to the pin:
I
SW
V
DD
f
SW
C××=
where
I
SW
is the current sunk by a switching I/O to charge/discharge the capacitive load
V
DD
is the MCU supply voltage
f
SW
is the I/O switching frequency
C is the total capacitance seen by the I/O pin: C = C
INT
+ C
EXT
The test pin is configured in push-pull output mode and is toggled by software at a fixed
frequency.