SFFS223A March 2022 – June 2025 UCC27531-Q1

4 Pin Failure Mode Analysis (Pin FMA)

This section provides a failure mode analysis (FMA) for the pins of the UCC27531-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 UCC27531-Q1 pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the UCC27531-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:

Pin short across the package is not considered.

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

Pin Name	Pin No.	Description of Potential Failure Effects	Failure Effect Class
EN	1	OUTH and OUTL always enabled and follows IN.	B
IN	2	OUTL is on. OUTH is off.	B
VDD	3	Device is not powered.	B
GND	4	Short to same potential. No impact.	D
OUTL	5	OUTL is always pulled down to GND. Possible OUTH and OUTL driver damage.	A
OUTH	6	OUTH is always pulled down to GND. Possible OUTH and OUTL driver damage.	A

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

Pin Name	Pin No.	Description of Potential Failure Effects	Failure Effect Class
EN	1	OUTH and OUTL are always enabled.	B
IN	2	OUTH is off and OUTL is on.	B
VDD	3	Device is not powered.	B
GND	4	OUTH and OUTL are pulled to VDD level.	B
OUTL	5	OUTL is not connected to power FET.	B
OUTH	6	OUTH is not connected to power FET.	B

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
EN	1	IN	Externally driven input pins are shorted. Device responds according to the voltage applied to the pins.	B
IN	2	VDD	OUTH is always on and OUTL is always off.	B
GND	4	OUTL	OUTL is always pulled down to GND. Possible OUTH and OUTL driver damage.	A
OUTL	5	OUTH	OUTH and OUTL output voltages are unknown. Possible OUTH and OUTL driver damage.	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
EN	1	Case 1: Device is always enabled.	B
EN	1	Case 2: Possible device damage VDD > 27V.	A
IN	2	Case 1: OUTH is ON and OUTL is off.	B
IN	2	Case 2: Possible device damage VDD > 27V.	A
VDD	3	Short to same potential. No impact.	D
GND	4	Device is not powered.	B
OUTL	5	Possible OUTH and OUTL driver damage.	A
OUTH	6	Possible OUTH and OUTL driver damage.	A