LPC1769 ADC in burst mode peaks every now and then

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by robert hulsebos on Mon Jul 14 00:49:34 MST 2014
We use the ADC of the LPC1769 in burst mode (no interrupts, no DMA). Just continuesly convert 4 stable voltages (4 channels) and read them at random periods using their indivual data registers. Not caring about OVERRUN.
Every now and then (may take minutes or even hours to reproduce) the AD0[1] conversion leads to peak value that is not plausible. (value outside range of possible values, but no 0xFFF)
VDDA and VREFP are bound to stable external ref voltage. Our oscilloscope never triggers on AD0[1] exceptional value, so no peak is there in hardware. Seems the ADC is seeing ghosts??

Anyone had similar experience?