 Hello and welcome to this presentation of the STM32 voltage reference buffer. It covers the main features of this block which creates an on-chip reference voltage. The VRF buffer embedded into STM32L4 microcontrollers provides a stable voltage based on an internal band gap reference for use by both the analog-to-digital and digital-to-analog converters. Its output voltage is programmable to 2.5 or 2.048 volts. This output voltage can also support external loads up to 4 milliamps. External bulk and bypass capacitors are required when the internal VRF 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 is common to use the analog supply as the reference voltage. By using this VRF 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. The VRF buffer is active in the following power modes. Run, Sleep, Low Power Run, Low Power Sleep, Stop 0 and Stop 1 modes. In Stop 2 mode, the VRF buffer is not available, but the contents of its registers are preserved. In standby and shutdown modes, the VRF buffer is powered down and it must be re-initialized after waking up from these modes. This table shows some performance parameters for the VRF buffer. The VRF buffer can work from 2.4 to 3.6 volts for a 2.048 volt output and 2.8 to 3.6 volts for a 2.5 volt output. The quiescent current is very small even with a 4 milliamp output current. It is possible to disable the VRF buffer when it is not being used. It can be available again 500 microseconds after it is re-enabled. The STM32L4's analog to digital and digital to analog converters use this VRF buffer output. Please refer to training modules for these peripherals for additional information.