Information

DocID022152 Rev 4 133/185
STM32F405xx, STM32F407xx Electrical characteristics
General PCB design guidelines
Power supply decoupling should be performed as shown in Figure 52 or Figure 53,
depending on whether V
REF+
is connected to V
DDA
or not. The 10 nF capacitors should be
ceramic (good quality). They should be placed them as close as possible to the chip.
Figure 52. Power supply and reference decoupling (V
REF+
not connected to V
DDA
)
1. V
REF+
and V
REF–
inputs are both available on UFBGA176. V
REF+
is also available on LQFP100, LQFP144,
and LQFP176. When V
REF+
and V
REF–
are not available, they are internally connected to V
DDA
and V
SSA
.
Figure 53. Power supply and reference decoupling (V
REF+
connected to V
DDA
)
1. V
REF+
and V
REF–
inputs are both available on UFBGA176. V
REF+
is also available on LQFP100, LQFP144,
and LQFP176. When V
REF+
and V
REF–
are not available, they are internally connected to V
DDA
and V
SSA
.
V
REF+
STM32F
V
DDA
V
SSA
/V
REF-
1 µF // 10 nF
1 µF // 10 nF
ai17535
(See note 1)
(See note 1)
V
REF+
/V
DDA
STM32F
1 µF // 10 nF
V
REF–
/V
SSA
ai17536
(See note 1)
(See note 1)