SFFS259 August 2021 TPSM53603
4 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
| 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 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.
Figure 4-1 Pin DiagramFollowing are the assumptions of use and the device configuration assumed for the pin FMA in this section:
- Application circuit, as per the TPSM53603 data sheet is used.
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 |