Mr. Quality Control Explains The Importance Of Clamping Diodes
Most semiconductors, particularly digital IC’s where inputs are exceptionally vulnerable to damage caused by over-voltage, have clamping diodes. Clamping diodes are used to protect the IC’s circuitry from electrostatic discharge (ESD), transients, voltage spikes and other causes of over-voltage. These diodes prevent damage to the IC by driving the unwanted current away from the main circuitry. We determine the part’s condition by testing its protection diodes. Clampdown Voltage Protection Diode (CVPD) testing includes: continuity (pin opens & shorts), damaged protection diodes, misalignment & disoriented, dice/lead frame, internal circuitry damage.
Pin-to-Pin resistance (PTPR) testing supports the CVPD testing. Adjacent signal pins, including supply pins, should not be shorted with one another unless noted. All ground pins must be shorted unless the device specification notes a defined resistance between them. With these criteria, CVPD and PTPR will effectively detect a different die with different diode and ground pin placements than an authentic unit and identifies counterfeit ICs. Pin-to-pin resistance (PTPR) testing: adjacent pin shorts, opens between ground pins resistance between two pins will be measured, identifies the number one cause of component failure.
White Horse Laboratories Limited