SFFS321 December 2021 DRV8908-Q1
This section provides a failure mode analysis (FMA) for the pins of the DRV8908-Q1. 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 DRV8908-Q1 pin diagram. For a detailed description of the device pins, see the Pin Configuration and Functions section in the DRV8908-Q1 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 Effect(s) | Failure Effect Class |
|---|---|---|---|
| GND | 1, 13, 24 | Normal function. | D |
| OUT1 | 2 | If OUT1 is commanded to be pulled high, short is detected and outputs are Hi-Z. | B |
| OUT5 | 3 | If OUT5 is commanded to be pulled high, short is detected and outputs are Hi-Z. | B |
| OUT7 | 4 | If OUT7 is commanded to be pulled high, short is detected and outputs are Hi-Z. | B |
| SDI | 5 | SPI communication is lost. | B |
| VDD | 6 | Device will be in SLEEP state and outputs are Hi-Z. | B |
| SDO | 7 | SPI communication is lost. | B |
| nSLEEP | 8 | Device will be in SLEEP state and outputs are Hi-Z. | B |
| NC | 9, 15, 17, 18 | Unused pin | D |
| OUT6 | 10 | If OUT6 is commanded to be pulled high, short is detected and outputs are Hi-Z. | B |
| OUT4 | 11 | If OUT4 is commanded to be pulled high, short is detected and outputs are Hi-Z. | B |
| nFAULT | 12 | False fault signalling possible. Device will continue to operate as commanded. | B |
| OUT3 | 14 | If OUT3 is commanded to be pulled high, short is detected and outputs are Hi-Z. | B |
| VM | 16, 21 | Device is powered off with driver Hi-Z. | B |
| nSCS | 19 | SPI communication is lost. | B |
| SCLK | 20 | SPI communication is lost. | B |
| OUT8 | 22 | If OUT8 is commanded to be pulled high, short is detected and outputs are Hi-Z. | B |
| OUT2 | 23 | If OUT2 is commanded to be pulled high, short is detected and outputs are Hi-Z. | B |
| Pin Name | Pin No. | Description of Potential Failure Effect(s) | Failure Effect Class |
|---|---|---|---|
| GND | 1, 13, 24 | Device is powered off with driver Hi-Z. | B |
| OUT1 | 2 | Load drive capability is lost. | B |
| OUT5 | 3 | Load drive capability is lost. | B |
| OUT7 | 4 | Load drive capability is lost. | B |
| SDI | 5 | SPI communication is lost. | B |
| VDD | 6 | Device will be in SLEEP state and outputs are Hi-Z. | B |
| SDO | 7 | SPI communication is lost. | B |
| nSLEEP | 8 | Device will be in SLEEP state and outputs are Hi-Z. | B |
| NC | 9, 15, 17, 18 | Unused pin | D |
| OUT6 | 10 | Load drive capability is lost. | B |
| OUT4 | 11 | Load drive capability is lost. | B |
| nFAULT | 12 | False fault signaling possible. Device will continue to operate as commanded. | B |
| OUT3 | 14 | Load drive capability is lost. | B |
| VM | 16, 21 | Device is powered off with driver Hi-Z. | B |
| nSCS | 19 | SPI communication is lost. | B |
| SCLK | 20 | SPI communication is lost. | B |
| OUT8 | 22 | Load drive capability is lost. | B |
| OUT2 | 23 | Load drive capability is lost. | B |
| Pin Name | Pin No. | Shorted to | Description of Potential Failure Effect(s) | Failure Effect Class |
|---|---|---|---|---|
| GND | 1 | GND | Normal function. | D |
| OUT1 | 2 | GND | If OUT1 is commanded to be pulled high, short is detected and OUT1 is Hi-Z. | B |
| OUT5 | 3 | OUT1 | Load drive capability is lost. | B |
| OUT7 | 4 | OUT5 | Load drive capability is lost. | B |
| SDI | 5 | OUT7 | SPI communication is lost. Low voltage pin max voltage may be violated. | A |
| VDD | 6 | SDI | SPI communication is lost. | B |
| SDO | 7 | VDD | SPI communication is lost. | B |
| nSLEEP | 8 | SDO | SPI communication is lost. | B |
| NC | 9 | nSLEEP | Short to unused pin. | D |
| OUT6 | 10 | NC | Short to unused pin. | D |
| OUT4 | 11 | OUT6 | Load drive capability is lost. | B |
| nFAULT | 12 | OUT4 | False fault signalling possible. Low voltage pin max voltage may be violated. | A |
| GND | 13 | nFAULT | False fault signalling possible. Device will continue to operate as commanded. | B |
| OUT3 | 14 | GND | If OUT3 is commanded to be pulled high, short is detected and OUT3 is Hi-Z. | B |
| NC | 15 | OUT3 | Short to unused pin. | D |
| VM | 16 | NC | Short to unused pin. | D |
| NC | 17 | VM | Short to unused pin. | D |
| NC | 18 | NC | Short to unused pin. | D |
| nSCS | 19 | NC | Short to unused pin. | D |
| SCLK | 20 | nSCS | SPI communication is lost. | B |
| VM | 21 | SCLK | SPI communication is lost. Low voltage pin max voltage may be violated. | A |
| OUT8 | 22 | VM | If OUT8 is commanded to be pulled low, short is detected and OUT8 is Hi-Z. | B |
| OUT2 | 23 | OUT8 | Load drive capability is lost. | B |
| GND | 24 | OUT2 | If OUT2 is commanded to be pulled high, short is detected and OUT2 is Hi-Z. | B |
| Pin Name | Pin No. | Description of Potential Failure Effect(s) | Failure Effect Class |
|---|---|---|---|
| GND | 1, 13, 24 | Device is powered off with driver Hi-Z. | B |
| OUT1 | 2 | If OUT1 is commanded to be pulled low, short is detected and outputs are Hi-Z. | B |
| OUT5 | 3 | If OUT5 is commanded to be pulled low, short is detected and outputs are Hi-Z. | B |
| OUT7 | 4 | If OUT7 is commanded to be pulled low, short is detected and outputs are Hi-Z. | B |
| SDI | 5 | SPI communication is lost. Low voltage pin max voltage may be violated. | A |
| VDD | 6 | Low voltage pin max voltage may be violated. | A |
| SDO | 7 | SPI communication is lost. Low voltage pin max voltage may be violated. | A |
| nSLEEP | 8 | Low voltage pin max voltage may be violated. | A |
| NC | 9, 15, 17, 18 | Short to unused pin. | D |
| OUT6 | 10 | If OUT6 is commanded to be pulled low, short is detected and outputs are Hi-Z. | B |
| OUT4 | 11 | If OUT4 is commanded to be pulled low, short is detected and outputs are Hi-Z. | B |
| nFAULT | 12 | Low voltage pin max voltage may be violated. | A |
| OUT3 | 14 | If OUT3 is commanded to be pulled low, short is detected and outputs are Hi-Z. | B |
| VM | 16, 21 | Normal function. | D |
| nSCS | 19 | SPI communication is lost. Low voltage pin max voltage may be violated. | A |
| SCLK | 20 | SPI communication is lost. Low voltage pin max voltage may be violated. | A |
| OUT8 | 22 | If OUT8 is commanded to be pulled low, short is detected and outputs are Hi-Z. | B |
| OUT2 | 23 | If OUT2 is commanded to be pulled low, short is detected and outputs are Hi-Z. | B |