SFFS765 July   2025 UCC27624-Q1

 

  1.   1
  2.   Trademarks
  3. 1Overview
  4. 2Functional Safety Failure In Time (FIT) Rates
    1. 2.1 D Package
    2. 2.2 DGN Package
    3. 2.3 DSD Package
  5. 3Failure Mode Distribution (FMD)
  6. 4Pin Failure Mode Analysis (Pin FMA)
  7. 5Revision History

4 Pin Failure Mode Analysis (Pin FMA)

This section provides a failure mode analysis (FMA) for the pins of the UCC27624-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, Figure 4-2, and Figure 4-3 show the UCC27624-Q1 pin diagrams. For a detailed description of the device pins, see the Pin Configuration and Functions section in the UCC27624-Q1 data sheet.

UCC27624-Q1 D Package Pin DiagramFigure 4-1 D Package Pin Diagram
Figure 4-2 DGN Package Pin Diagram
Figure 4-3 DSD Package Pin Diagram

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

  • Pin 1 shorted to pin 8 and pin 4 shorted to pin 5 are not considered.
  • The case of a short-circuit to supply is analyzed as a short to VDD.
Table 4-2 Pin FMA for Device Pins Short-Circuited to Ground
Pin Name Pin No. Description of Potential Failure Effects Failure Effect Class
ENA 1 The ENA function is disabled. OUTA does not respond to INA. B
INA 2 The INA function is lost. OUTA is stuck low. B
GND 3 No impact. D
INB 4 The INB function is lost. OUTB is stuck low. B
OUTB 5 OUTB is stuck low. OUTB is short circuited if INB is commanded High. A
VDD 6 There is a VDD undervoltage. OUTA and OUTB are off. B
OUTA 7 OUTA is stuck low. OUTA is short circuited if INA is commanded High. A
ENB 8 The ENB function is disabled. OUTB does not respond to INB. B
Table 4-3 Pin FMA for Device Pins Open-Circuited
Pin Name Pin No. Description of Potential Failure Effects Failure Effect Class
ENA 1 OUTA is always enabled. OUTA responds to INA. B
INA 2 The INA function is lost. OUTA is stuck low. B
GND 3 The state of OUTA and OUTB are unknown. B
INB 4 The INB function is lost. OUTB is stuck low. B
OUTB 5 OUTB is disconnected from the power FET. B
VDD 6 There is a VDD undervoltage. OUTA and OUTB are off. B
OUTA 7 OUTA is disconnected from the power FET. B
ENB 8 OUTB is always enabled. OUTB responds to INB. 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
ENA 1 INA ENA cannot override the INA command. OUTA responds to INA. B
INA 2 GND OUTA is stuck low. B
GND 3 INB OUTB is stuck low. B
OUTB 5 VDD OUTB is stuck high. A
VDD 6 OUTA OUTA is stuck high. A
OUTA 7 ENB The ENB function depends on the state of INA (OUTA). B
Table 4-5 Pin FMA for Device Pins Short-Circuited to Supply
Pin Name Pin No. Description of Potential Failure Effects Failure Effect Class
ENA 1 OUTA is always enabled. OUTA responds to INA. B
INA 2 OUTA is stuck high. B
GND 3 The power supply is short circuited. B
INB 4 OUTB is stuck high. B
OUTB 5 OUTB is stuck high. A
VDD 6 No impact. D
OUTA 7 OUTA is stuck high. A
ENB 8 OUTB is always enabled. OUTB responds to INB B