National LM5111-1M Dual 5A Compound Gate Drivers

Gideon AnalyticalLaboratories received four National LM5111-1M dual 5A compound gate drivers. Two were failed and two were operational. A gate driver is power amplifier that accepts a low-power input from a controller IC and produces a high-current drive input for the gate of a high-power transistor such as an IGBT or power MOSFET. Gate drivers can be provided either on-chip or as a discrete module. In essence, a gate driver consists of a level shifter in combination with an amplifier. We received no information as to why theNational LM5111-1M dual 5A compound gate drivers were failing. But that never stopped Gideon Analytical Laboratories before. The goal was to determine the cause of the failures.

Electronic failure analysis ensued on this components. TheNational LM5111-1M dual 5A compound gate drivers. There was no mechanical damage to the plastic or lead frame of the 8-pin SOIC gate driver. The failed devices, as well as the good devices, were tested using a curve tracer to determine the condition of each lead. Both failed devices had dead short from the Vee to Vcc (pin 3 to pin 6). Each measured about 2.8 ohms. The package was decapsulated. The failure site was hard to not notice. They had burn marks. The site had broken down the step coverage oxide between subcutaneous ground and the Vcc supply. The second failure was identical to the first: dead short from Vcc to Vee. Most likely, these failures were the cause of improper application.

For Gideon Analytical Laboratories, getting to the root cause of this failure was like using silver in your circuitry: there was little resistance. With the speed and accuracy that typifies our work, we got the job done. If you are questioning why your parts are failing, contact us. Are you worried about lawsuits? Fires? Liability? Bad publicity? Do you want to have the peace of mind that your products work with reliability? We can help you. Give Gideon Analytical Laboratories a call today.

Closer image second failure

Closer image second failure

National LM5111-1M dual 5A

National LM5111-1M dual 5A

Failure sites

Failure sites

Problem area is circled

Problem area is circled

Second failure identical to the first

Second failure identical to the first

Package after decapsulation

Package after decapsulation