A reference voltage loss monitoring circuit having a first and second reference node. The reference nodes are connected to a voltage reference. A first connection device is connects the first reference node to the second reference node, and includes a first diode to allow a current flowing from the first reference node to the reference ground node and not conversely. The first diode includes a first main transistor. A second connection device connects the second reference node to the first reference node, and includes a second diode to allow a current flowing from the second reference node to first reference node and not conversely. The second diode includes a second main transistor. Each of the first and second connection devices further includes a secondary transistor mirrored with the main transistor of the connection devices. The secondary transistor has an output coupled to a diagnostic circuit, for delivering to the diagnostic circuit a signal indicative of a loss of voltage reference on a respective reference node.