SFFS341 February 2022 LM5163

4 Pin Failure Mode Analysis (Pin FMA)

This section provides a Failure Mode Analysis (FMA) for the pins of the LM5163. 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 supply (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.

Table 4-1 TI Classification of Failure Effects

Class	Failure Effects
A	Potential device damage that affects functionality
B	No device damage, but loss of functionality
C	No device damage, but performance degradation
D	No device damage, no impact to functionality or performance

Figure 4-1 shows the LM5163 pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the LM5163 data sheet.

Figure 4-1 Pin Diagram

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

Application circuit, as per the LM5163, LM5163-Q1, LM5164, and LM5164-Q1 data sheets, is used
- PGOOD is pulled up to VOUT

Table 4-2 Pin FMA for Device Pins Short-Circuited to Ground

Pin Name	Pin No	Description of Potential Failure Effect(s)	Failure Effect Class
GND	1		D
VIN	2	VOUT = 0 V	B
EN/UVLO	3	VOUT = 0 V	B
RON	4	VOUT unregulated; 0 ≤ VOUT < set voltage	B
FB	5	VOUT >> set voltage. PGOOD can become damaged if VIN > 14 V.	A
PGOOD	6	PGOOD is invalid flag.	B
BST	7	VOUT = 0 V	B
SW	8	Power FET damage	A

Table 4-3 Pin FMA for Device Pins Open-Circuited

Pin Name	Pin No	Description of Potential Failure Effect(s)	Failure Effect Class
GND	1	VOUT = 0 V	B
VIN	2	VOUT = 0 V	B
EN/UVLO	3	VOUT = 0 V	B
RON	4	VOUT > set voltage	B
FB	5	VOUT >> set voltage. PGOOD can become damaged if VIN > 14 V.	A
PGOOD	6	PGOOD flag invalid	B
BST	7	VOUT = 0 V	B
SW	8	VOUT = 0 V	B

Table 4-4 Pin FMA for Device Pins Short-Circuited to Adjacent Pin

Pin Name	Pin No	Description of Potential Failure Effect(s)	Failure Effect Class
GND	1	VOUT = 0 V	B
VIN	2		D
EN/UVLO	3	VIN > 5.5 V can lead to device damage.	A
RON	4	VOUT < set voltage	B
FB	5	PGOOD flag invalid. VOUT can be unregulated.	A
PGOOD	6	VOUT = 0 V	B
BST	7	VOUT = 0 V	B
SW	8	VOUT = 0 V	B

Table 4-5 Pin FMA for Device Pins Short-Circuited to Supply

Pin Name	Pin No	Description of Potential Failure Effect(s)	Failure Effect Class
GND	1	VOUT = 0 V	B
VIN	2		D
EN/UVLO	3		D
RON	4	VIN > 5.5 V can lead to device damage.	A
FB	5	VIN > 5.5 V can lead to device damage.	A
PGOOD	6	VIN > 14 V can lead to device damage.	A
BST	7	VOUT = 0 V	B
SW	8	VOUT = VIN. PGOOD can be damaged if VIN > 14 V.	A