  We analyse the implications of the Wilkinson Microwave Anisotropy Probe
(WMAP) results for a braneworld tachyonic model of inflation. We find that WMAP
bounds on $n_s$ allow us to constrain significantly the parameter space of the
model; in particular, extremely weak string coupling is required, $g_s \sim
10^{-15}$. Moreover, our analysis shows that the running of the scalar spectral
index is within the bounds determined by WMAP for the allowed range of model
parameters; however, it is not possible to obtain $n_s>1$ on large scales and
$n_s<1$ on small scales.
