Powering-up a board under test on the Medalist i3070 Series 5 in-circuit tester
is the pre-condition before the execution of any digital tests on the integrated
circuit (IC). ICs on boards may be internally powered by on-board regulators. The
on-board regulators can be affected during the testing or debugging procedures,
which may cause the regulators to switch off unintentionally due to interference
to its enable pins.
This increases the potential difference between the driven signal pins and the
internal voltage rail of the IC and thus, can potentially cause damage to the IC
pins (protection circuit), as driving continues without power on the voltage rails.
The IC will be electrically stressed if testing continues under this “over voltage”
condition.
This will incur a lot of rework, manpower and material cost if the IC malfunctions.