SFFS192 March   2022 UCC5350-Q1 , UCC5390-Q1

 

  1.   Trademarks
  2. 1Overview
  3. 2Functional Safety Failure In Time (FIT) Rates
  4. 3Failure Mode Distribution (FMD)
  5. 4Pin Failure Mode Analysis (Pin FMA)

4 Pin Failure Mode Analysis (Pin FMA)

This section provides a Failure Mode Analysis (FMA) for the pins of the UCC5350-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
ClassFailure Effects
APotential device damage that affects functionality
BNo device damage, but loss of functionality
CNo device damage, but performance degradation
DNo device damage, no impact to functionality or performance

Figure 4-1 shows the UCC5350-Q1 pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the UCC5350-Q1 data sheet.

Figure 4-1 Pin Diagram

Figure 4-2 shows the UCC5390-Q1 pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the UCC5390-Q1 data sheet.

Figure 4-2 Pin Diagram

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

  • Primary side short to positive potential is short to Vcc1 and Vcc2 for the seondary.
  • Pin short from #1 to #8 and #4 to #5 are not considered.
  • Pin short that result in system supply fault cases are considered no effect to the driver.
Table 4-2 Pin FMA for Device Pins Short-Circuited to Ground
Pin NamePin No.Description of Potential Failure Effect(s)Failure Effect Class
Vcc11Device is not powered.D
IN+2OUT stuck low.B
IN-3Cross conduction prevention does not work..B
GND1 4 Short to same potential. No effect. D
Vcc2 5 Seondary side unpowered. D
OUT 6 OUT stuck low. Potential damage to OUT driver. A
CLAMP(UCC5350-Q1) 7 CLAMP stuck low. Potentail damage to OUT and CLAMP driver. A
GND2 (UCC5390-Q1) 7 Short to same potentail. No effect. D
VEE2 8 Short to same potential. No effect. D
Table 4-3 Pin FMA for Device Pins Open-Circuited
Pin Name Pin No. Description of Potential Failure Effect(s) Failure Effect Class
Vcc1 1 Device is unpowered. D
IN+ 2 OUT stuck low. B
IN- 3 OUT stuck low B
GND1 4 Device is unpowered. D
Vcc2 5 Device is unpowered. D
OUT 6 OUT is disconnected from the power stage gate. B
CLAMP(UCC5350-Q1) 7 Miller Clamp function is not available. B
GND2 (UCC5390-Q1) 7 Device is unpowered. OUT stuck high. B
VEE2 8 Device is unpowered. OUT stuck high. B
Table 4-4 Pin FMA for Device Pins Short-Circuited to Adjacent Pin
Pin NamePin No.Shorted toDescription of Potential Failure Effect(s)Failure Effect Class
Vcc11IN+OUT follows IN- command.B
IN+2IN-OUT depends on IN+ and IN- driving capability.B
IN-3GND1Cross conduction prevention does not work..B
Vcc2 5 OUT OUT stcuk high. Potantail damage to OUT driver. A
OUT(UCC5390-Q1) 6 GND2 OUT stcuk low. Potantail damage to OUT driver. A
OUT(UCC5350-Q1) 6 CLAMP No effect on the driver. The external gate resistor may be shorted out. D
GND2(UCC5390-Q1) 7 VEE2 System supply short. No effect to the driver. D
CLAMP (UCC5350-Q1) 7 VEE2 CLAMP stuck low. Potential damage to OUT driver. A
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
Vcc1 1 No effect. Short to same potentail. D
IN+ 2 OUT follows IN- command. B
IN- 3 OUT stuck low. B
GND1 4 Device is unpowered. D
Vcc2 5 No effect. Short to same potentail. D
OUT 6 OUT stuck high. Potential damage to OUT driver. A
CLAMP(UCC5350-Q1) 7 CLAMP stuck high. Potential damage to OUT and CLAMP driver. A
GND2 (UCC5390-Q1) 7 Device is unpowered. D
VEE2 8 Device is unpowered. D