Analog-to-Digital Converter (ADC)
MCF52211 ColdFire® Integrated Microcontroller Reference Manual, Rev. 2
26-38 Freescale Semiconductor
VREFH is as noise-free as possible. Any noise residing on the VREFH voltage is directly transferred to the
digital result.
Figure 26-28 illustrates the internal workings of the ADC voltage ref erence circuit. VREFH must be noise
filtered; a minimum configuration is shown in the figure.
26.5.11 Supply Pins VDDA and VSSA
Dedicated power supply pins are provided for the purposes of reducing noise coupling and to improve
accuracy. The power provided to these pins is suggested to come from a low noise filtered source.
Uncoupling capacitors ought to be connected between VDDA and VSSA.