Methods and apparatus are provided for testing a magnetoresistive random
access memory (MRAM). A magnetoresistive tunnel junction (MTJ) has a
first terminal, a second terminal, and a third terminal. A source
measuring unit is coupled to a first terminal of a MTJ to provide DC
biasing. A current preamp has an input coupled to a third terminal of the
MTJ for receiving current corresponding to a resistance of the MTJ. A
pulse generator is AC coupled to the MTJ for programming the MTJ. A
method of insitu testing a MTJ in a manufacturing environment uses a
probe station coupled to the MTJ. A probe station couples to the MTJ. The
MTJ is DC biased for generating a current corresponding to the logic
level stored in the MTJ. A pulse for programming the MTJ is AC coupled to
the MTJ.