SFFSAG0 June 2025 TPS22950-Q1
4 Pin Failure Mode Analysis (Pin FMA)
This section provides a failure mode analysis (FMA) for the pins of the TPS22950-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.
| 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 TPS22950-Q1 pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the TPS22950-Q1 data sheet.
Figure 4-1 Pin DiagramFollowing are the assumptions of use and the device configuration assumed for the pin FMA in this section:
- The device pins are connected per the recommendation in the data sheet, including pullup and pulldown resistors, as needed.
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| ON | 1 | The device turns off. | B |
| VIN | 2 | The power supply is shorted. | D |
| GND | 3 | This is the intended operation for the GND pin. | D |
| ILIM | 4 | The current limit block does not limit the current. | A |
| VOUT | 5 | If the current limit is set, the device tries to limit the current to a value set by ILIM. | B |
| FLT | 6 | Grounding this pin does not allow the device to indicate the fault properly. | C |
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| ON | 1 | The device is off. The device does not pass through voltage to VOUT. | B |
| VIN | 2 | No power supply to the device. The device does not pass through voltage to VOUT. | D |
| GND | 3 | No ground to the device. The device does not function. | D |
| ILIM | 4 | The current limit block does not function correctly. | B |
| VOUT | 5 | The output does not deliver the voltage to the load. | D |
| FLT | 6 | There is no pullup to read the Fault pin status. | D |
| Pin Name | Pin No. | Shorted to | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|---|
| ON | 1 | VIN | The device is enabled if the VIN power supply is above the ON threshold (VIH). | D |
| VIN | 2 | GND | The device does not have power supply. | D |
| ILIM | 4 | VOUT | Incorrect current limit function. The device potentially turns off and on since the current limit threshold depends on the voltage of the VOUT pin. | B |
| VOUT | 5 | FLT | No effect during no fault. During a fault condition, the Fault pin can conduct large amounts of current from VOUT to GND. | A |
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| ON | 1 | Normal operation is expected. | D |
| VIN | 2 | Normal operation is expected. | D |
| GND | 3 | The power supply is shorted. | D |
| ILIM | 4 | The device does not turn on. | B |
| VOUT | 5 | The power MOSFET is shorted. Disabling the device no longer blocks power to VOUT. | B |
| FLT | 6 | During a fault condition, the Fault pin draws huge amounts of current; potentially damaging the pin. | A |