SFFSAU7 December 2025 TPS2HC08-Q1
4 Pin Failure Mode Analysis (Pin FMA)
This section provides a failure mode analysis (FMA) for the pins of the TPS2HC08-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 VBB 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 TPS2HC08-Q1 pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the TPS2HC08-Q1 datasheet.
Figure 4-1 Pin Diagram for VAH (QFN, 11)Following 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 datasheet, including pullup and pulldown resistors, as needed.
- The datasheet recommendations for operating conditions, external component selection, and PCB layout are followed.
Table 4-2 Pin FMA for Device Pins Short-Circuited to Ground
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| VOUT1 | 1 | The current limit of the device engages, and thermal protection turns off the FET of CH1. | B |
| VBB | 2 | The output stages are not powered, and the FET of both channels do not turn ON. | B |
| ILIM | 3 | The current limit is set at a maximum level, as per the data sheet. | C |
| GND | 4 | Any GND network, connected for protection, is bypassed. | B |
| SEL | 5 | The reported SNS current or fault status on the SNS pin is always of CH1 when the DIAG_EN pin is high. | B |
| DIAG_EN | 6 | The diagnostic features do not function, including current sense and fault reporting. | B |
| EN1 | 7 | The FET of CH1 is turned off and an erroneous open-load fault reports for no-load conditions when the DIAG_EN pin is high. | B |
| EN2 | 8 | The FET of CH2 is turned off and an erroneous open-load fault reports for no-load conditions when the DIAG_EN pin is high. | B |
| SNS | 9 | The reported SNS current or fault status on the SNS pin is erroneous. | B |
| FLT | 10 | The reported fault status is potentially erroneous. | B |
| VOUT2 | 11 | The current limit of the device engages, and thermal protection turns off the FET of CH2. | B |
Table 4-3 Pin FMA for Device Pins Open-Circuited
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| VOUT1 | 1 | During the ON state of the device, CH1 is disconnected. During the OFF state of the device, if the DIAG_EN pin is high, an open-load fault reports. | B |
| VBB | 2 | The device is not powered and both the channels are kept OFF. | B |
| ILIM | 3 | The current limit is set at a minimum level, as per the data sheet. | C |
| GND | 4 | The loss of ground detection engages, and the device turns OFF. | B |
| SEL | 5 | The reported SNS current or fault status on the SNS pin is always of CH1 when the DIAG_EN pin is high. (internal pulldown). | B |
| DIAG_EN | 6 | The diagnostic features do not function, including current sense and fault reporting. (internal pulldown). | B |
| EN1 | 7 | The FET of CH1 is turned off and an erroneous open-load fault reports for no-load conditions when the DIAG_EN pin is high (internal pulldown). | B |
| EN2 | 8 | The FET of CH2 is turned off and an erroneous open-load fault reports for no-load conditions when the DIAG_EN pin is high (internal pulldown). | B |
| SNS | 9 | The current sense and fault at the SNS pin is not reported. | B |
| FLT | 10 | The fault condition is not reported. | B |
| VOUT2 | 11 | During the ON state of the device, CH2 is disconnected. During the OFF state of the device, if the DIAG_EN pin is high, an open-load fault reports. | B |
Table 4-4 Pin FMA for Device Pins Short-Circuited to Adjacent Pin
| Pin Name | Pin No. | Shorted to | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|---|
| VOUT1 | 1 | VOUT2 | Loss of individual channel control. The current sensing and fault reported on the SNS and FLT pins are potentially erroneous. | B |
| VBB | 2 | VOUT1 | The output of CH1 is pulled to the supply voltage. A short-to-battery detection triggers during the OFF state if the DIAG_EN pin is high. | B |
| ILIM | 3 | VBB | There is a loss of the current limit setting based on the RLIM resistor. | C |
| GND | 4 | ILIM | The current limit is set at a maximum level, as per the data sheet. | C |
| SEL | 5 | GND | There is a loss of control of the SEL pin and the reported current or fault status of the SNS pin is always of CH1 when the DIAG_EN pin is high. | B |
| DIAG_EN | 6 | SEL | There is a loss of control of the DIAG_EN and SEL pins and the current and fault reporting of the SNS pin is erroneous. | B |
| EN1 | 7 | DIAG_EN | There is a loss of enable control of CH1 and open-load fault detection is erroneous for CH1 when the DIAG_EN pin is high. | B |
| EN2 | 8 | EN1 | There is a loss of enable control for both channels (CH1 and CH2) and an erroneous fault is potentially reported at the SNS and FLT pins when the DIAG_EN pin is high. | B |
| SNS | 9 | EN2 | The reported SNS current or fault status on the SNS pin is erroneous and there is a loss of enable control for CH2. | B |
| FLT | 10 | SNS | The reported fault status and voltage of the SNS pin is potentially erroneous. | B |
| VBB | 2 | FLT | The reported fault status is potentially erroneous. | B |
| VOUT2 | 11 | VBB | The output of CH2 is pulled to the supply voltage. A short-to-battery detection triggers during the OFF state if the DIAG_EN pin is high. | B |
Table 4-5 Pin FMA for Device Pins Short-Circuited to VBB Supply
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| VOUT1 | 1 | The output of CH1 is pulled to the supply voltage. A short-to-battery detection triggers during the OFF state if the DIAG_EN pin is high. | B |
| VBB | 2 | No effect. | D |
| ILIM | 3 | There is a loss of the current limit setting based on the RLIM resistor. | C |
| GND | 4 | The supply power is bypassed, and the device stays OFF. | B |
| SEL | 5 | There is a potential violation of the absolute maximum rating for the pin and a possible breakdown of the ESD cell. | A |
| DIAG_EN | 6 | There is a potential violation of the absolute maximum rating for the pin and a possible breakdown of the ESD cell. | A |
| EN1 | 7 | There is a potential violation of the absolute maximum rating for the pin and a possible breakdown of the ESD cell. | A |
| EN2 | 8 | There is a potential violation of the absolute maximum rating for the pin and a possible breakdown of the ESD cell. | A |
| SNS | 9 | There is a potential violation of the absolute maximum rating for the pin and a possible breakdown of the ESD cell. | A |
| FLT | 10 | The reported fault status is potentially erroneous. | B |
| VOUT2 | 11 | The output of CH2 is pulled to the supply voltage. A short-to-battery detection triggers during the OFF state if the DIAG_EN pin is high. | B |