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Pull up resistor in STM32WBA5MMG RESET circuit
Dear Team,
I have a board contain STM32WBA5MMG and AD5941. We have provided a single RESET for both the chips.
The circuit is given below.
May Iknow will this cause any issues.
Regards
Hiyo
Peter BENSCHBest answer
ST Technical Moderator
April 24, 2026
No STM32 requires a pull-up resistor at the reset pin (in your case R36 = DNP), because there is already an internal pull-up present (see RM0493, 12.3.2).
The reset pin also acts as an output if an internal reset is triggered in the STM32, so any devices externally connected to NRST also receive this reset signal. According to the data sheet, the AD5941 needs at least 1µs to detect a reset; the internal pulse generator in the STM32 typically produces a pulse that is at least 20µs long (unfortunately, the specification for tO(NRST) is mentioned in RM0493 but still missing from the data sheet of the STM32WBA55UG, however, the pulse generator should be identical to that of other STM32 devices).
Summary: In my humble opinion, there should be no problem connecting /RESET and NRST.
Regards
/Peter
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