STM32L412: No decoupling caps for VDDA if not used?

[AN..1]

Hi there,

I'm designing an application with an STM32L412K8 and I don't use ADC, OPAMP or COMP. The datasheet (DS12469) says:

1. VDDA shall be 0 to 3.6 V if ADC, OPAMP, COMP is not used (general operating conditions table 21).
2. When the functions supplied by VDDA are not used, this supply should preferably be shorted to VDD (power supply schemes page 19).

Does this mean that I can just connect VDDA to VDD without any decoupling capacitors?

Thank you in advance!

[Tesla DeLorean]

In STM32 designs VDDA typically powers the POR circuit, so if you're not using other analogue functions you can simply bond the supplies, and just retain any decoupling/bulk capacitance you have on VDD, serving the usual purpose, the CMOS switching currents/noise aren't going to trigger the POR.

Leaving VDDA unconnected is a primary cause of the part not starting as expected, as the NRST is clamped to GND

[Piranha]

Actually AN4555 tells that for L4 series POR/BOR, clocks and other mandatory "peripherals" are connected to VDD and VDDA is indeed only for ADC, DAC, OPAMP, COMP and reference buffer.

Anyway for both topologies the answer is yes.