4 Pin Failure Mode Analysis (Pin FMA)

This section provides a failure mode analysis (FMA) for the pins of the LM5168 and LM5169. The failure modes covered in this document include the typical pin-by-pin failure scenarios:

• Pin short-circuited to ground (see Table 4-2)
• Pin open-circuited (see Table 4-3)
• Pin short-circuited to an adjacent pin (see Table 4-4)
• Pin short-circuited to VIN (see Table 4-5)

Table 4-2 through Table 4-5 also indicate how these pin conditions can affect the device as per the failure effects classification in Table 4-1.

Figure 4-1 and Figure 4-2 show the LM5168 and LM5169 pin diagrams for the HSOIC and WSON packages, respectively. For a detailed description of the device pins, see the Pin Configuration and Functions section in the LM5168 and LM5169 data sheets.

Following are the assumptions of use and the device configuration assumed for the pin FMA in this section:

• Device used within the Recommended Operating Conditions and the Absolute Maximum Ratings found in LM5169, LM5168 0.65-A/0.3-A, 120-V, Step-Down Converter with Fly-Buck™ Converter Capability Data Sheet
• Configuration as shown in the Example Application Circuit found in the LM5169, LM5168 0.65-A/0.3-A, 120-V, Step-Down Converter with Fly-Buck™ Converter Capability Data Sheet.
• Valid for an ambient temperature of 25°C.
• Faults applied after device start-up is complete.