SFFS074 March 2021 TPS3702
4 Pin Failure Mode Analysis (Pin FMA)
This section provides a Failure Mode Analysis (FMA) for the pins of the TPS3702. 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 VDD (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 TPS3702 pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the TPS3702 data sheet.
Figure 4-1 DDC PackageSOT-6Top ViewFollowing are the assumptions of use and the device configuration assumed for the pin FMA in this section:
- Unless otherwise specified, it is assumed that the voltages applied to all the pins are within the Recommended Operating Range specified in the TPS3702 data sheet.
- Note that the SET and the SENSE pin have lower maximum operating range than VDD and UV/OV.
- For shorts to VDD, this document assumes the SET and SENSE pin maximum is not exceeded.
- Refer to Typical Application Circuit diagram in the datasheet for test layout.
Table 4-2 Pin FMA for Device Pins Short-Circuited to
Ground
| Pin Name | Pin No. | Description of Potential Failure Effect(s) | Failure Effect Class |
|---|---|---|---|
| UV | 1 | No damage to device, undervoltage output pin nonfunctional, increase in system current. | B |
| GND | 2 | No effect. | D |
| SENSE | 3 | No damage to device, Undervoltage output always active, Overvoltage output always inactive. | B |
| OV | 4 | No damage to device, Overvoltage output pin nonfunctional, increase in system current. | B |
| VDD | 5 | No damage to device, but device is unpowered. Device is nonfunctional. | B |
| SET | 6 | No damage to device, wide thresholds selected. | B |
Table 4-3 Pin FMA for Device Pins
Open-Circuited
| Pin Name | Pin No. | Description of Potential Failure Effect(s) | Failure Effect Class |
|---|---|---|---|
| UV | 1 | No damage to device, undervoltage output pin nonfunctional. | B |
| GND | 2 | No damage to device, but device is unpowered. Device is nonfunctional. | B |
| SENSE | 3 | No damage to device. Due to internal resistor ladder for setting trip points open SENSE pin behaves as though GND potential - Undervoltage output always active, Overvoltage output always inactive. | B |
| OV | 4 | No damage to device, overvoltage output pin nonfunctional. | B |
| VDD | 5 | No damage to device, but device is unpowered. Device is nonfunctional. | B |
| SET | 6 | No damage to device. Due to internal pull up on SET pin it behaves as if connected to VDD - narrow thresholds selected. | B |
Table 4-4 Pin FMA for Device Pins Short-Circuited to
Adjacent Pin
| Pin Name | Pin No. | Shorted to | Description of Potential Failure Effect(s) | Failure Effect Class |
|---|---|---|---|---|
| UV | 1 | GND | No damage to device, undervoltage output pin nonfunctional, increase in system current. | B |
| GND | 2 | SENSE | No damage to device, Undervoltage output always active, Overvoltage output always inactive. | B |
| SENSE | 3 | SET | Since SET VIH = 750mV and all SENSE thresholds >1V, SENSE = SET means always narrow threshold tolerances selected. | B |
| OV | 4 | UV | No damage to device, but device is nonfunctional with both outputs tied together, can’t distinguish OV from UV. | B |
| VDD | 5 | OV | No damage to device, overvoltage output pin nonfunctional. | B |
| SET | 6 | VDD | No damage to device, narrow thresholds selected. | B |
Table 4-5 Pin FMA for Device Pins Short-Circuited to
VDD
| Pin Name | Pin No. | Description of Potential Failure Effect(s) | Failure Effect Class |
|---|---|---|---|
| UV | 1 | No damage to device, undervoltage output pin nonfunctional. | B |
| GND | 2 | No damage to device, but device is unpowered. Device is nonfunctional. | B |
| SENSE | 3 | No damage to device, Undervoltage output always inactive, Overvoltage output always active. | B |
| OV | 4 | No damage to device, overvoltage output pin nonfunctional. | B |
| VDD | 5 | No effect. | D |
| SET | 6 | No damage to device, narrow thresholds selected. | B |