The IDC's mobile device technology and trends team have revealed that sales of standalone PDAs have fallen by almost 40% year-on-year.

In the fifteenth straight quarter of sales decline, just 728,894 PDAs were sold worldwide in Q3 of this year, down 39.3% on the same quarter last year.

"The handheld device market has been under constant pressure, with mobile phones and converged mobile devices appropriating many of the handheld's salient attributes", says Ramon T. Llamas, research analyst with IDC.

Its stated that strong growth in the smartphone market is mainly to blame for the decline, but that the form factor is not quite dead yet. "The handheld device market may be down, but is not necessarily out", says Llamas.

"The handheld still has a loyal, if shrinking, following in developed economies, especially among enterprise users."

Palm is top of what sales there are, with HP, Mio, Sharp and Fujitsu-Siemens, who recently announced their exit from the PDA market, completing the top five.