SFFSAG0 June 2025 TPS22950-Q1

4 Pin Failure Mode Analysis (Pin FMA)

This section provides a failure mode analysis (FMA) for the pins of the TPS22950-Q1. 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 TPS22950-Q1 pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the TPS22950-Q1 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:

The device pins are connected per the recommendation in the data sheet, including pullup and pulldown resistors, as needed.

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

Pin Name	Pin No.	Description of Potential Failure Effects	Failure Effect Class
ON	1	The device turns off.	B
VIN	2	The power supply is shorted.	D
GND	3	This is the intended operation for the GND pin.	D
ILIM	4	The current limit block does not limit the current.	A
VOUT	5	If the current limit is set, the device tries to limit the current to a value set by ILIM.	B
FLT	6	Grounding this pin does not allow the device to indicate the fault properly.	C

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

Pin Name	Pin No.	Description of Potential Failure Effects	Failure Effect Class
ON	1	The device is off. The device does not pass through voltage to VOUT.	B
VIN	2	No power supply to the device. The device does not pass through voltage to VOUT.	D
GND	3	No ground to the device. The device does not function.	D
ILIM	4	The current limit block does not function correctly.	B
VOUT	5	The output does not deliver the voltage to the load.	D
FLT	6	There is no pullup to read the Fault pin status.	D

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

Pin Name	Pin No.	Shorted to	Description of Potential Failure Effects	Failure Effect Class
ON	1	VIN	The device is enabled if the VIN power supply is above the ON threshold (VIH).	D
VIN	2	GND	The device does not have power supply.	D
ILIM	4	VOUT	Incorrect current limit function. The device potentially turns off and on since the current limit threshold depends on the voltage of the VOUT pin.	B
VOUT	5	FLT	No effect during no fault. During a fault condition, the Fault pin can conduct large amounts of current from VOUT to GND.	A

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

Pin Name	Pin No.	Description of Potential Failure Effects	Failure Effect Class
ON	1	Normal operation is expected.	D
VIN	2	Normal operation is expected.	D
GND	3	The power supply is shorted.	D
ILIM	4	The device does not turn on.	B
VOUT	5	The power MOSFET is shorted. Disabling the device no longer blocks power to VOUT.	B
FLT	6	During a fault condition, the Fault pin draws huge amounts of current; potentially damaging the pin.	A