Can I use the precision voltage reference output to supply current to external devices?
When using the internal precision voltage reference, it is not recommended to use the output as a source for external components. Measurements errors can occur since errors induced on the reference voltage are directly passed to the analog measurements.
If the system is required to use the reference connected to external components, then the load regulation of the reference must be maintained. The current sourced by the reference cannot exceed the current specified in the data sheet to maintain the accuracy of the reference. For example, the EFM8LB1 8-bit MCU specifies load regulation at 200 µA. This current value should not be exceeded to maintain proper operation. An external buffer amplifier can also be used to minimize the interference of the reference.