Where is the exact definition/derivation of the Vrefint (1.23 V) of STM32F302x MCU?

[AHeck.1]

Hello,

according the datasheet for "STM32F302x6 STM32F302x8" -> "6.3.4 Embedded reference voltage" there is the definition of Vrefint as 1.23 V.

But how exactly is it generated / derivated?

I also checked the advanced Arm®-based 32-bit MCUs - Reference manual, but i cant find anything regarding this.

Im using in my project the MCU "STM32F302C8T6 - LQFP48 Pin" and want to understand the calculation and derivation of this topic.

I didnt found an electrical schematic regarding the 1.23V or topology.

Thanks in advance.

[MasterT]

Check the datasheet

https://www.st.com/en/microcontrollers-microprocessors/stm32f302c8.html

Regarding schematic, my guess is, it's build the same way as TL431. Exact topology likely proprietor, and would never be published. Same as topology of the adc, dac, opa or comp, those analog peripherals have specification but very little details on the internal whereabouts.

[S.Ma]

Wikipedia on bandgap voltage. Structure which relies on process rather than supply voltage, temperature, etc... This way, vdd ran be deducted from vref adc measurement.

[AScha.3]

about this is there on chip: