 Hello, and welcome to this presentation of the STM32G4 voltage reference buffer. It covers the main features of this block, which creates a non-chip reference voltage. The VREF buffer embedded in STM32G4 microcontrollers provides a stable voltage based on an internal bandgap reference for use by both the analog-to-digital and digital-to-analog converters. Its output voltage is programmable to 2.0, 2.5 or 2.048 volts. This output voltage can also support external loads up to 6.5 milliamps. External bulk and bypass capacitors are required when the internal VREF buffer is used. Applications can benefit from this on-chip voltage reference as it eliminates the need for an expensive external standalone reference voltage IC. For space-constrained systems, it's common to use the analog supply as the reference voltage. By using this VREF buffer instead, it can create a stable voltage even if the analog supply is changing, for example when the VDDA supply comes from a battery output. Two reference voltage values can be chosen. Each of the three selectable VREF buff voltages implies a minimum value of VDDA power supply. The VREF plus pin can deliver up to 6.5 milliamps. In this case, the VREF buff consumption from VDDA is 45 microamps. The voltage is held with the external capacitor. In the 32 pin packages, since the VREF plus pin is double bonded with the VDDA pin, the voltage reference buffer is not available and must be kept disabled. The internal voltage reference can be configured in four different modes depending on ENVR and HIZ bits configuration. After enabling the VREF buff buffer by setting ENVR bit and clearing HIZ bit in the VREF buff CSR register, the user must wait until the VREF bit is set, meaning that the voltage reference output has reached its expected value. When an external voltage reference is implemented, VREF plus pin is an input. When VREF buff is used as an internal voltage reference, it is output on VREF plus pin in order to provide this reference to external devices. The VREF buffer is active in the following power modes, run, sleep, low power run, low power sleep, stop zero and stop one mode. In standby and shutdown modes, the VREF buffer is powered down and it must be reinitialized after waking up from these modes. This table shows certain performance parameters for the VREF buffer. The VREF buffer can work from 2.4 to 3.6V for a 2.048V output, 2.8 to 3.6V for a 2.5V output and 3.135 to 3.6V for a 2.9V output. The queer send current is very small, even with a 6.5mA output current. It's possible to disable the VREF buffer when it's not being used. It can be available again 500 microseconds after it is re-enabled. The DC power supply rejection is 55 decibels. The STM32G4's analog to digital and digital to analog converters use this VREF buffer output. Please refer to the training modules for these peripherals for additional information.