  We analyze the consequences of the hypothesis that the formation of the Broad
Line Region is intrinsically connected with the existence of the cold accretion
disk. We assume that the Broad Line Region radius is well estimated by the
formula of Kaspi et al. (2000). We consider three models of the disappearance
of the inner disk which limit the existence of the Broad Line Region: (i)
classical ADAF approach, i.e. the inner hot flow develops whenever it can exist
(ii) disk evaporation model of Meyer & Meyer-Hofmeister (2002) (iii)
generalized disk evaporation model of Rozanska & Czerny (2000b). For each of
the models, we determine the minimum value of the Eddington ratio and the
maximum value of the broad line widths as functions of the viscosity parameter
alpha and the magnetic field parameter beta. We compare the predicted parameter
space with observations of several AGN. Weak dependence of the maximum value of
the FWHM and minimum value of the Eddington ratio on the black hole mass in our
sample is noticeable. It seems to favor the description of the cold disk/hot
inner flow transition as in the classical ADAF approach than with the model of
disk evaporation due to conduction between the disk and accreting corona.
