SFFSAR6 August 2025 TPS3842
This section provides a failure mode analysis (FMA) for the pins of the TPS3842. The failure modes covered in this document include the typical pin-by-pin failure scenarios:
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 TPS3842 pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section of the TPS3842 data sheet.
Following are the assumptions of use and the device configuration assumed for the pin FMA in this section:
| Pin Name | Pin No. | Description Of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| VDD | 1 | VDD short to GND; device has no power for normal operation. | B |
| SENSE | 2 | RESET asserts. | B |
| RESET | 3 | Forces RESET low. | B |
| CTS | 4 | RESET is unable to assert. | B |
| GND | 5 | No damage to the device. No impact to the functionality of the device. | D |
| CTR | 6 | RESET asserts normally but does not deassert. | B |
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| VDD | 1 | Device is not powered. | B |
| SENSE | 2 | No damage to the device. Reset asserts. | B |
| RESET | 3 | Reset functionality is lost since reset is not pulled up to VDD. | B |
| CTS | 4 | Normal operation. | D |
| GND | 5 | Device is not powered. | B |
| CTR | 6 | Normal operation. | D |
| Pin Name | Pin No. | Shorted To | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|---|
| VDD | 1 | SENSE | Normal functionality if SENSE is monitoring VDD rail. RESET asserts if VDD < Vitn. | D |
| 2 | ||||
| SENSE | 2 | RESET | RESET follows VSENSE; giving instances of wrong outputs. | C |
| 3 | ||||
| CTS | 4 | GND | RESET is unable to assert. | B |
| 5 | ||||
| GND | 5 | CTR | RESET asserts normally but does not deassert. | B |
| 6 |
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| VDD | 1 | No damage to the device. No impact to the functionality of the device. | D |
| SENSE | 2 | RESET asserts if VDD < Vitn; otherwise, normal functionality. | D |
| RESET | 3 | Forces RESET high. | B |
| CTS | 4 | No damage to the device. No impact to the functionality of the device. | D |
| GND | 5 | GND short to VDD; device has no power for normal operation. | D |
| CTR | 6 | RESET asserts. | B |