SFFS259 August   2021 TPSM53603

 

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

Pin Failure Mode Analysis (Pin FMA)

This section provides a Failure Mode Analysis (FMA) for the pins of the TPSM53603. 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 TPSM53603 pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the TPSM53603 data sheet.

GUID-8FF538DE-7DB1-449F-A6AA-904F5C08C59E-low.gif Figure 4-1 Pin Diagram

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

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
VIN 1, 14 Device will not operate. No output voltage will be generated. Output capacitors will discharge through input short. Large reverse current can damage device. A
EN 2 Loss of ENABLE functionality. Device will remain in Shutdown mode. B
NC 3, 10, 11 Not connected to any circuitry within the module; no effect D
DNC 4, 5 Possible damage to internal circuits A
PGOOD 6 This is a valid connection for PGOOD output. PGOOD functionality will be lost. Damage to customer components connected to PGOOD input can occur. B
VOUT 7, 8 Loss of output voltage B
FB 9 The regulator will operate at maximum duty cycle. Output voltage will rise to nearly the input voltage (VIN) level. Possible damage to customer load, output stage components can occur, or both. No effect on device. B
AGND 12 No effect D
V5V 13 Fault mode will shut down device. B
PGND 15 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
VIN 1, 14 With both pins open: loss of output voltage. With one pin open: possible device damage. A
EN 2 Loss of enable functionality. Erratic operation; probable loss of regulation B
NC 3, 10, 11 Not connected to any circuitry within the module; no effect D
DNC 4, 5 No effect D
PGOOD 6 This is a valid connection for the PGOOD output. PGOOD functionality will be lost. B
VOUT 7, 8 Loss of output voltage B
FB 9 Loss of output volage regulation. Output voltage can rise or fall outside of intended regulation window. B
AGND 12 Loss of output voltage regulation. Possible damage to internal circuits A
V5V 13 This is a valid connection for V5V pin. D
PGND 15 Erratic operation; probable loss of regulation. Possible device damage A
Table 4-4 Pin FMA for Device Pins Short-Circuited to Adjacent Pin
Pin Name Pin No. Shorted to Description of Potential Failure Effect(s) Failure Effect Class
VIN 1 EN This is a valid input for VIN. Enable functionality will be lost; the device will remain on. B
EN 2 NC Loss of enable functionallity. Probable loss of regulation B
NC 3 DNC NC pin is not connected to any circuitry within the module; no effect D
DNC 4 DNC Possible damage to internal circuits A
DNC 5 PGOOD Possible damage to internal circuits A
PGOOD 6 VOUT Possible damge to internal circuits A
VOUT 7 PGND Loss of output voltage B
VOUT 8 FB Erratic operation; probable loss of regulation. Damage to internal circuits will occur for VOUT > 5.5 V. A
FB 9 NC NC pin not connected to any circuitry within the module; no effect D
NC 10 NC Neither pin connected to any circuitry within the module; no effect D
NC 11 AGND NC pin not connected to any circuitry within the module; no effect D
AGND 12 V5V Fault mode will shut down device. B
V5V 13 VIN Damage to internal circuits for VIN > 5.5 V A
VIN 14 PGND Device will not operate. No output voltage will be generated. Output capacitors will discharge through input short. Large reverse current can damage device. 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
VIN 1, 14 No effect. D
EN 2 No damage to device. Loss of enable functionality. B
NC 3, 10, 11 No effect. C
DNC 4, 5 Possible damage to internal circuits. A
PGOOD 6 Damage to internal circuits. A
VOUT 7, 8 The output voltage will rise to nearly the level of VIN. Customer load will be damaged. Possible damage to device. A
FB 9 Damage to internal circuits will occur for VIN > 5.5 V. A
AGND 12 Possible damage to internal circuits or package. A
V5V 13 Damage to internal circuits for VIN > 5.5 V. A
PGND 15 Device will not operate. No output voltage will be generated. Output capacitors will discharge through input short. Large reverse current may damage device. A