Central AC Unit - Intake is very cold
AFIK the main cause of freezing on the evaporator coil is low refrigerant. This may sound counter-intuitive but it is a well known accepted fact.

There may be other possible causes. I think the blower is supposed to continue for a short period after the compressor cycles off and your unit may not be doing that. Call a competent a/c tech. This is not a DIY project.

From original poster:


  a tech . . . discovered that the switch
  to turn the outside unit on and off was bad. It would sometimes stick
  open and other times closed. The result was that although the inside
  unit turned off, the outside unit continued to run.