I present a XMM-Newton observation of the accretion driven millisecond X-ray pulsar SAX J1808.4–3658 during its 2000 outburst .
The source was conclusively detected , albeit at a level of only \sim 2 \times 10 ^ { 32 } erg s ^ { -1 } .
The source spectrum could be fitted with a power-law model ( with a photon index of \sim 2.2 ) , a neutron star atmosphere model ( with a temperature of \sim 0.2 keV ) , or with a combination of a thermal ( either a black-body or an atmosphere model ) and a power-law component .
During a XMM-Newton observation taken approximately one year later , the source was in quiescence and its luminosity was a factor of \sim 4 lower .
It is possible that the source spectrum during the 2000 outburst was softer than its quiescent 2001 spectrum , however , the statistics of the data do not allow to make a firm conclusion .
The results obtained are discussed in the context of the 2000 outburst of SAX J1808.4–3658 and the quiescent properties of the source .