Lpc2000

Does anyone know what is the maximum speed that I could send
data to the D/A at fixed frequency?

I am using a LPC2148 with a 10MHz crystal and a PLL M value of 6, and
P value of 2.  My PCLK should be 60Mhz (VPBDIV=0x1)

I have tried setting up a timer to send a sample every 1uS, but the
output appears to be quite unstable.

  Thank you