SFFS807 June 2024 TCAN3403-Q1 , TCAN3404-Q1
4 Pin Failure Mode Analysis (Pin FMA)
This section provides a failure mode analysis (FMA) for the pins of the TCAN340x-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 VCC (see Table 4-5)
- Pin short-circuited to VBAT (see Table 4-6)
- Pin short-circuited to VIO (Table 4-7)
Table 4-2 through Table 4-7 also indicate how these pin conditions can affect the device as per the failure effects classification in Table 4-1.
Following are the assumptions of use and the device configuration assumed for the pin FMA in this section:
- VCC = 3V to 3.6V
- VBAT = 6V to 24V
- VIO = 1.7V to 3.6V
- The VSON thermal pad is not connected to device GND and is only for thermal purposes.
- No bus fault condition is considered while evaluating pin shorts.
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 TCAN340x-Q1 SOIC pin diagram. Figure 4-2 shows the TCAN340x-Q1 VSON pin diagram. Figure 4-3 shows the TCAN340x-Q1 SOT pin diagram. For a detailed description of the device pins, see the Pin Configuration and Functions section in the TCAN340x-Q1 data sheets.
Figure 4-1 SOIC Pin DiagramFigure 4-3 SOT Pin Diagram
Figure 4-2 VSON Pin DiagramTable 4-2 Pin FMA for Device Pins Short-Circuited to Ground
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| TXD | 1 | Device enters dominant time out mode. Unable to transmit data. | B |
| GND | 2 | None. | D |
| VCC | 3 | Device not powered, high ICC current. | B |
| RXD | 4 | RXD default is high-side FET ON, with pin short to ground, forms direct path between supply and ground causing high current. | A |
| SHDN | 5 | Device is unable to enter ultra-low power shutdown mode. | B |
| VIO | 5 | Device is in protected mode. Transceiver passive on bus. | B |
| CANL | 6 | VO(REC) specification violated. Degraded EMC performance. | C |
| CANH | 7 | Device cannot drive dominant to the bus, no communication is possible. | B |
| STB | 8 | STB stuck low, transceiver is unable to enter low-power mode. | B |
| Thermal Pad | - | None. | D |
Note: The VSON package includes a thermal pad.
Table 4-3 Pin FMA for Device Pins Open-Circuited
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| TXD | 1 | TXD pin defaults high, device is always recessive and unable to transmit data. | B |
| GND | 2 | Device not powered. | B |
| VCC | 3 | Device not powered. | B |
| RXD | 4 | No RXD output, unable to receive data. | B |
| SHDN | 5 | Device remains in active mode due to integrated pull-down. | B |
| VIO | 5 | Device is in protected mode. Transceiver passive on bus. | B |
| CANL | 6 | Device cannot drive dominant on the bus, unable to communicate. | B |
| CANH | 7 | Device cannot drive dominant on the bus, unable to communicate. | B |
| STB | 8 | STB pin defaults high, transceiver stuck in low-power mode. | B |
| Thermal Pad | - | None. | D |
Note: The VSON package includes a thermal pad.
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 |
|---|---|---|---|---|
| TXD | 1 | GND | Device enters dominant time out mode. Unable to transmit data. | B |
| GND | 2 | VCC | High current can flow through GND pin, transceiver can be damaged. | A |
| VCC | 3 | RXD | RXD output stuck high, unable to receive data. | B |
| SHDN | 5 | CANL | Device experiences disrupted CAN communication and there is potential for unintended shutdown behavior. | B |
| VIO | 5 | CANL | Bus stuck recessive, no communication is possible. IOS current can be reached on CANL. | B |
| CANL | 6 | CANH | Bus stuck recessive, no communication possible. IOS current can be reached on CANH/CANL. | B |
| CANH | 7 | STB | Driver and receiver turn off when a dominant is driven. May not enter normal mode. | B |
Note:
- The VSON package includes a thermal pad. All device pins are adjacent to the thermal pad. The device behavior, when pins are shorted to the thermal pad, depends on which net is connected to the thermal pad.
- For a GND shorted to VCC scenario, the device can be damaged if:
- VCC is shorted to GND
- VCC pin is soldered to VCC route with supply ON
- The GND pin is not soldered to system ground
- The SHDN or STB pins are soldered to system GND
Table 4-5 Pin FMA for Device Pins Short-Circuited to VCC
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| TXD | 1 | TXD stuck high, unable to transmit data. | B |
| GND | 2 | High current can flow through GND pin, transceiver can be damaged. | A |
| VCC | 3 | None. | D |
| RXD | 4 | RXD pin stuck high, unable to receive data. | B |
| SHDN | 5 | Device enters ultra-low power shutdown mode. | B |
| VIO | 5 | IO pins operate as 3.3V input/outputs. Microcontroller can be damaged if VCC > VIO. | C |
| CANL | 6 | RXD is always recessive, no communication is possible. IOS current can be reached. | B |
| CANH | 7 | VO(REC) specification is violated, degraded EMC performance. | C |
| STB | 8 | STB stuck high, transceiver is always in standby mode. | B |
Table 4-6 Pin FMA for Device Pins Short-Circuited to VBAT
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| TXD | 1 | Absolute maximum violation, transceiver can be damaged. Unable to transmit data. | A |
| GND | 2 | Device not powered, high IBAT current. | B |
| VCC | 3 | Absolute maximum violation, transceiver can be damaged. Bus can be unable to communicate. | A |
| RXD | 4 | Absolute maximum violation, transceiver can be damaged. Unable to receive data. | A |
| SHDN | 5 | Absolute maximum violation, transceiver can be damaged. | A |
| VIO | 5 | Absolute maximum violation, transceiver can be damaged. | A |
| CANL | 6 | RXD is always recessive, no communication is possible. IOS current can be reached. | B |
| CANH | 7 | VO(REC) specification violated, degraded EMC performance. | C |
| STB | 8 | Absolute maximum violation, transceiver can be damaged. Transceiver stuck in low-power mode. | A |
Table 4-7 Pin FMA for Device Pins Short-Circuited to VIO
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| TXD | 1 | TXD stuck high, unable to transmit data. | B |
| GND | 2 | High current can flow through GND pin, transceiver can be damaged. | A |
| VCC | 3 | IO pins operate as 5V input/outputs. Microcontroller can be damaged if VCC > VIO. | C |
| RXD | 4 | RXD pin stuck high, unable to receive data. | B |
| SHDN | 5 | None, as there is not a VIO pin for the device having an SHDN pin. | D |
| VIO | 5 | None. | D |
| CANL | 6 | RXD is always recessive, no communication is possible. IOS current can be reached if VIO ≥ 3.3V. | B |
| CANH | 7 | VO(REC) specification is violated if VIO ≥ 3.3V, degraded EMC performance. | C |
| STB | 8 | STB stuck high, transceiver is always in standby mode. | B |
Note: Table 4-7 is only applicable to the TCAN3403-Q1 device.
- For a GND shorted to VIO scenario, the device can be damaged if:
- VIO is shorted to GND
- VIO pin is soldered to VIO route with supply ON
- The GND pin is not soldered to system ground
- The STB pins are soldered to system GND