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STM32U575QII Dedicated OPAMP2_VINM pin not connected?

Tomas Hamouz
Associate III

I have a project which uses both OPAMPs. For both OA I use dedicated VINM pin.

OPAMP1 works correctly.

OPAMP2 behaves like the dedicated pin (M2 ball) is not connected to the input multiplexer.

I 've tried

 - mode FOLLOWER: OK

 - mode STANDALONE, reconnected the signal on the board and used PA7 for VINM: OK

 - mode STANDALONE, using the dedicated pin: the output is saturated at VDDA.

Checked the PCB connection, OK. Checked on 3 boards, identical results.

Is it possible it is really a bug in the silicon? What else should I check?

(I would like to use OPAMP tag, but it is not available :(  )

 

Initialization code:

(GPIO to analog)

LL_APB3_GRP1_EnableClock(LL_APB3_GRP1_PERIPH_OPAMP);

LL_OPAMP_InitTypeDef OPAMP_Init;

OPAMP_Init.PowerMode = LL_OPAMP_POWERMODE_NORMALPOWER_NORMALSPEED;
OPAMP_Init.FunctionalMode = LL_OPAMP_MODE_STANDALONE;
OPAMP_Init.InputNonInverting = LL_OPAMP_INPUT_NONINVERT_IO0;
OPAMP_Init.InputInverting = LL_OPAMP_INPUT_INVERT_IO1;
LL_OPAMP_Init(OPAMP2, &OPAMP_Init);

LL_OPAMP_Enable(OPAMP2);

 

 

 

 

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