DocID027496 Rev 1

5/24

AN4658

Hardware migration guide

23

1

Hardware migration guide

Except for the LQFP100 and LQFP144 packages, the STM32F446xx devices are fully

pin-to-pin compatible with the STM32F429xx/439xx devices, allowing the user to try

different peripherals, and reaching higher performance (higher frequency) for a greater

degree of freedom during the development cycle.

The transition from the STM32F429/439 lines to the STM32F446 line is simple since only a

few pins are impacted, as summarized in Table 2.

1.1

Recommendations for board migration

For the LQFP100 package PB11 is not available anymore and it is replaced by VCAP1.

For the LQFP144 the PCB change is mandatory only when an external ULPI PHY is used in

USB HS mode, otherwise no PCB update is needed.

A dedicated VDDUSB supply is used on STM32F446 and it is available only on LQFP144,

UFBGA144 and WLCSP81 packages.

The pin PDR_ON used on STM32F429 to enable power supervisor is now managed in

static way.

Figure 1 and Figure 2 show two examples of board designs migrating from STM32F429 to

STM32F446.

Table 2. Pinout comparison (LQFP packages)

STM32F429xx/439xx

STM32F446xx

QFP100 QFP144

Pinout

QFP100 QFP144

Pinout

48

-

PB11

48

-

VCAP1

49

-

VCAP1

49

-

VSS

1. For the LQFP144 the PCB change is mandatory only when an external ULPI PHY is used in USB HS

mode, otherwise no PCB update is needed.

PB11 (OTG_HS_ULPI_D4)

-

70(1)

PB11

-48(1)

PB2

-

48(1)

PB2 (OTG_HS_ULPI_D4)

-

95

VDD

-

95

VDDUSB