SFFS049 March 2021 TPS61379-Q1
4 Pin Failure Mode Analysis (Pin FMA)
This section provides a Failure Mode Analysis (FMA) for the pins of the TPS61379-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 VIN (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 TPS61379-Q1 pin diagram. For a detailed description of the device pins please refer to the 'Pin Configuration and Functions' section in the TPS61379-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:
- Device used within the Recommended Operating Conditions and the Absolute Maximum Ratings found in the TPS61379-Q1 data sheet.
- Configuration as shown in the Application and Implementation section found in the TPS61379-Q1 data sheet.
Table 4-2 Pin FMA for
Device Pins Short-Circuited to Ground
| Pin Name | Pin No. | Description of Potential Failure Effects(s) | Failure Effect Class |
|---|---|---|---|
| VIN | 1 | The device does not operate. Power supply is short. | B |
| BST | 2 | Possible device damage | A |
| SW | 3 | Potential damage to inductor and pin | A |
| SW | 4 | Potential damage to inductor and pin | A |
| MODE/SYNC | 5 | The device remains in Auto PFM mode. Loss of forced PWM mode, spread spectrum functionality, and frequency synchronization functionality | C |
| VCC | 6 | Output voltage out of regulation | B |
| GND | 7 | No effect | D |
| GND | 8 | No effect | D |
| VO | 9 | The device remains in hiccup output short circuit protection mode. | B |
| OUT | 10 | Potential damage to device | A |
| PG | 11 | Correct output voltage. Loss of PG functionality | C |
| NC | 12 | No effect | D |
| FB | 13 | Output voltage is regulated to 5 V. | B |
| COMP | 14 | No output voltage | B |
| EN | 15 | Loss of ENABLE functionality. The device remains in Shut Down mode. | B |
| FREQ | 16 | Switching frequency is 2 MHz typically. | C |
Table 4-3 Pin FMA for Device Pins
Open-Circuited
| Pin Name | Pin No. | Description of Potential Failure Effects(s) | Failure Effect Class |
|---|---|---|---|
| VIN | 1 | The device does not work. Output voltage is 0 V. | B |
| BST | 2 | The device is damaged. | A |
| SW | 3 | Possible device damage | A |
| SW | 4 | Possible device damage | A |
| MODE/SYNC | 5 | Device remains in auto PFM mode. Loss of Forced PWM mode, spread spectrum functionality, and frequency synchronization functionality | C |
| VCC | 6 | High ripple on VCC pin. Efficiency is lower. | C |
| GND | 7 | Possible device damage | A |
| GND | 8 | Possible device damage | A |
| VO | 9 | No output voltage | B |
| OUT | 10 | Possible device damage | A |
| PG | 11 | Correct output voltage. Loss of PG functionality | C |
| NC | 12 | No effect | D |
| FB | 13 | Output voltage is out of regulation. | B |
| COMP | 14 | Output voltage is out of regulation. | B |
| EN | 15 | Loss of ENABLE functionality. The device remains in Shut Down mode. | B |
| FREQ | 16 | No output voltage | 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(s) | Failure Effect Class |
|---|---|---|---|---|
| VIN | 1 | BST | Possible device damage | A |
| BST | 2 | SW | Output voltage out of regulation | B |
| SW | 3 | SW | No effect | D |
| SW | 4 | MODE/SYNC | Possible device damage | A |
| MODE/SYNC | 5 | VCC | The device remains in forced PWM mode. Loss of Auto PFM mode and frequency synchronization functionality | C |
| VCC | 6 | GND | The device does not work. VOUT = 0 V | B |
| GND | 7 | GND | No effect | D |
| GND | 8 | VO | The device remains in hiccup output short circuit protection mode. | B |
| VO | 9 | OUT | Loss of Down mode functionality and hiccup output short circuit protection | B |
| OUT | 10 | PG | Possible device damage | A |
| PG | 11 | NC | Potential device damage if PG is pulled up to higher than 6 V. | A |
| NC | 12 | FB | No effect | D |
| FB | 13 | COMP | No output voltage | B |
| COMP | 14 | EN | OVP is triggered | B |
| EN | 15 | FREQ | No output voltage | B |
| FREQ | 16 | VIN | The FREQ pin is damaged if supply voltage is higher than 6 V. | A |
Table 4-5 Pin FMA for Device Pins Short-Circuited to
VIN
| Pin Name | Pin No. | Description of Potential Failure Effects(s) | Failure Effect Class |
|---|---|---|---|
| VIN | 1 | No effect | D |
| BST | 2 | Possible device damage | A |
| SW | 3 | Damage to internal power FETs | A |
| SW | 4 | Damage to internal power FETs | A |
| MODE/SYNC | 5 | The MODE/SYNC pin damaged if supply voltage is higher than 6 V. | A |
| VCC | 6 | VCC pin is damaged if supply voltage is higher than 6 V. | A |
| GND | 7 | Possible device damage due to large current | A |
| GND | 8 | Possible device damage due to large current | A |
| VO | 9 | VO = VIN | B |
| OUT | 10 | The device remains in Hiccup mode. No output voltage | B |
| PG | 11 | Possible device damage | A |
| NC | 12 | The NC pin is damaged if supply voltage is higher than 6 V. | A |
| FB | 13 | The FB pin is damaged if supply voltage is higher than 6 V. | A |
| COMP | 14 | The COMP pin is damaged if supply voltage is higher than 6 V. | A |
| EN | 15 | The EN pin is damaged if supply voltage is higher than 6 V. | A |
| FREQ | 16 | The FREQ pin is damaged if supply voltage is higher than 6 V. | A |