  Quantum Diamond Microscope (QDM) magnetic field imaging is an emerging
interrogation and diagnostic technique for integrated circuits (ICs). To date,
the ICs measured with a QDM were either too complex for us to predict the
expected magnetic fields and benchmark the QDM performance, or were too simple
to be relevant to the IC community. In this paper, we establish a 555 timer IC
as a "model system" to optimize QDM measurement implementation, benchmark
performance, and assess IC device functionality. To validate the magnetic field
images taken with a QDM, we used a SPICE electronic circuit simulator and
Finite Element Analysis (FEA) to model the magnetic fields from the 555 die for
two functional states. We compare the advantages and the results of three
IC-diamond measurement methods, confirm that the measured and simulated
magnetic images are consistent, identify the magnetic signatures of current
paths within the device, and discuss using this model system to advance QDM
magnetic imaging as an IC diagnostic tool.
