Photocoupler Avago HCPL 0630 Failure Analysis

Gideon Analytical Labs received one failed photocoupler, an Avago HCPL 0630 in an 8 pin DIP SOIC -8 package. The reported failure came from the field after approximately 1.5 years of operation.

The HCPL-0630 optocoupler is an optically coupled logic gate that combines a GaAsP light emitting diode and an integrated high gain photo detector. An enable input allows the detector to be strobed. The output of the detector IC is an open collector Schottky-clamped transistor.

This unique design provides maximum ac and dc circuit isolation while achieving TTL compatibility. The optocoupler ac and dc operational parameters are guaranteed from -40 degrees C to 85 degrees C allowing trouble free system performance.

HCPL-0630 is suitable for a high-speed logic interfacing, input/output buffering, as line receivers in environments that conventional line receivers cannot tolerate and is recommended for use in extremely high ground or induced noise environments.

The input diodes were tested continuously from room temperature to 120C with no intermittent or abnormal curve traces. There was no surface inversion, no leakage current and no indication of moisture present in the package. The inputs operated normally in every respect up to 120C where the test was terminated. The transistor did not output terminals when the input diode was excited. The photo-transistor was examined and tested to elucidate the failure mode. The failure site was a blown Vcc trace to ground interconnect. This was probably a weakness in the step coverage insulator as it went under the VCC trace line. The spot shows a blown spot where the lines have arced. Metal is in an area beside the trace line under the passivation layer. Normally when this happens to a good device, the entire area has burned rather than a spot. This failure mode is more than likely a manufacturing anomaly rather than an application overstress.

Four years later, the phototransistors have not failed in the field supporting the conclusion made. Call Gideon Analytical Labs for your failure analysis of capacitors, transistors, FETs, diode, rectifiers, PCBs, or any electrical device. We are here to help solve problems.