Gideon Analytical labs received one FDN337N-channel FET for failure analysis. The Drain-Source was reported shorted. Super SOTTM-3 N-Channel logic level enhancement mode power field effect transistors are produced using Fairchild’s high cell density DMOS technology. This very high-density process is specially tailored to minimize on-state resistance.
These devices are particularly suited for low voltage applications in notebook computers, portable phones, PCMCIA cards, and other battery powered circuits where fast switching and low in-line power loss are needed in a very small outline surface mount package.
Gideon Analytical Labs received two failed TI UCC27223PWP and three vintage devices for comparison. Two 14 pin Dip TI UCC27223PWP functional failures were sent from assemblies. The UCC27223 is a high-speed synchronous buck driver for thigh-efficiency lower-output voltage designs. Using PredictiveGate Drive (PGD) control technology, these drivers reduce diode conduction and reverse recovery losses in the synchronous rectifier MOSFET(s). The UCC27223 has an enable pin that controls the operation of both outputs.
Gideon Analytical Labs received one SCR (silicon-controlled rectifier) module FP25001P1 for failure analysis.
An SCR consists of four layers of alternating p- and n-type semiconductor materials, NPNP or PNPN structures. The three P-N junctions are labeled J1, J2 and, J3, for the three terminals. Silicon is used as the intrinsic semiconductor, to which the proper dopants are added. The junctions are either diffused or alloyed (an alloy is a mixed semiconductor or a mixed metal).
Gideon Analytical Labs received one failed 1N5626GP diode and several good ones for comparison. According to a Wikipedia post, a p–n junction diode is made of a crystal of a semiconductor, usually silicon, but germanium href=“https://en.wikipedia.org/wiki/Gallium_arsenide">gallium arsenide are also used. Impurities are added to it to create a region on one side that contains negative charge carriers (electrons), called an n-type semiconductor, and a region on the other side that contains positive charge carriers (holes), called a p-type semiconductor.
Gideon Analytical Labs received the main PCB that had a fire in one section of the board. The objective was to find the cause in an already established product line.
This PCB had some copper deposition problems at level two copper. The deposition was seen under the diode mounted to the PCB. The deposited copper also was responsible for an internal short within the PCB. The internal short caused the electrolytic capacitor to heat up and vent toward the PCB surface onto a hot trace line.
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.
Gideon Analytical Labs received one failed photocoupler, a Vishay IL 420, for failure analysis along with two virgins (unused) optocouplers for comparison.
The basic function of a Photo Coupler is to have electronic isolation, including potential isolation (as in the case of the transformer) in an electrical circuit. Devices of the Photo Coupler family include Photo Transistor, Photo Darlington Transistor, Photo Triac and OPIC. These devices have the characteristics of excellent isolation, high CTR, compact package, high-speed operation, low decay and unit control function not being influenced by field effects.
Gideon Analytical Labs received one failed ST Microelectronics BTA06 Triac a TO-220AB package. The device was reported to have failed post-burn-in.
This Triac is suitable for general purpose AC switching according to ST Micro. They can be used as an ON/OFF function in applications such as static relays, heating regulation, induction motor starting circuits or for phase control operation in light dimmers, motor speed controllers. The specially recommended for use on inductive loads, thanks to their high commutation performances.
Gideon Analytical Labs received three-failed Fairchild RFP40N10 power MOSFETs. All the terminals were shorted. A MOSFET is a voltage-controlled power device. If no positive voltage is applied between gate and source, the MOSFET will be non-conducting. If a positive voltage is applied to the gate an electrostatic field between it and the rest of the transistor will be produced. This positive gate voltage will push away the holes inside the p-type substrate and attracts the movable electrons in the n-type regions under the source and drain electrodes.
Gideon Analytical Labs received one failed multilayer ceramic capacitor for failure analysis. The image below is from Wikipedia. It shows the standard metallurgy for MLCCs.
The capacitor was mounted to the PCB and showed no signs of external damage. The capacitor was removed from the PCB and tested. The leakage current was too high for a capacitor of this size. The capacitor failure analysis revealed by a cross-section that the capacitor had thermal cracks extending from one side to the other.
