FUNCTIONAL SAFETY FIT RATE, FMD AND PIN-FMA
TCAN1046-Q1 and TCAN1046V-Q1 Functional Safety FIT Rate, FMD and Pin FMA
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1 Overview
This document contains information for TCAN1046-Q1 and TCAN1046V-Q1 (VSON package) to aid in a functional safety system design. Information provided are:
- Functional Safety Failure In Time (FIT) rates of the semiconductor component estimated by the application of industry reliability standards
- Component failure modes and their distribution (FMD) based on the primary function of the device
- Pin failure mode analysis (Pin FMA)
Figure 1-1 shows the TCAN1046-Q1 functional block diagram for reference. Figure 1-2 shows the TCAN1046V-Q1 functional block diagram for reference.
Figure 1-1 TCAN1046-Q1 Functional Block
Diagram
Figure 1-2 TCAN1046V-Q1 Functional Block DiagramTCAN1046-Q1 and TCAN1046V-Q1 were developed using a quality-managed development process, but were not developed in accordance with the IEC 61508 or ISO 26262 standards.
2 Functional Safety Failure In Time (FIT) Rates
This section provides Functional Safety Failure In Time (FIT) rates for TCAN1046-Q1/TCAN1046V-Q1 based on two different industry-wide used reliability standards:
- Table 2-1 provides FIT rates based on IEC TR 62380 / ISO 26262 part 11
- Table 2-2 provides FIT rates based on the Siemens Norm SN 29500-2
Table 2-1 Component Failure Rates per IEC TR 62380 / ISO 26262 Part 11
| FIT IEC TR 62380 / ISO 26262 | FIT (Failures Per 109 Hours) 14-pin VSON (DMT) |
|---|---|
| Total Component FIT Rate | 9 |
| Die FIT Rate | 3 |
| Package FIT Rate | 6 |
The failure rate and mission profile information in Table 2-1 comes from the Reliability data handbook IEC TR 62380 / ISO 26262 part 11:
- Mission Profile: Motor Control from Table 11
- Power dissipation: 250 mW
- Climate type: World-wide Table 8
- Package factor (lambda 3): Table 17b
- Substrate Material: FR4
- EOS FIT rate assumed: 0 FIT
Table 2-2 Component Failure Rates per Siemens Norm SN 29500-2
| Table | Category | Reference FIT Rate | Reference Virtual TJ |
|---|---|---|---|
| 5 | CMOS,
BICMOS Digital, analog / mixed | 20 FIT | 55°C |
The Reference FIT Rate and Reference Virtual TJ (junction temperature) in Table 2-2 come from the Siemens Norm SN 29500-2 tables 1 through 5. Failure rates under operating conditions are calculated from the reference failure rate and virtual junction temperature using conversion information in SN 29500-2 section 4.
3 Failure Mode Distribution (FMD)
The failure mode distribution estimation for TCAN1046-Q1 and TCAN1046V-Q1 in Table 3-1 comes from the combination of common failure modes listed in standards such as IEC 61508 and ISO 26262, the ratio of sub-circuit function size and complexity and from best engineering judgment.
The failure modes listed in this section reflect random failure events and do not include failures due to misuse or overstress.
Table 3-1 Die Failure Modes and Distribution
| Die Failure Modes | Failure Mode Distribution (%) |
|---|---|
| Receiver Fail | 45% |
| Transmitter Fail | 45% |
| CANH or CANL driver stuck dominant | 5% |
| Short circuit any two pins | 5% |
4 Pin Failure Mode Analysis (Pin FMA)
This section provides a Failure Mode Analysis (FMA) for the pins of the TCAN1046-Q1 and TCAN1046V-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 4-6)
- Pin short-circuited to VIO (see Table 4-7)
- Pin short-circuited to VBAT (see Table 4-8)
Table 4-2 through Table 4-8 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 TCAN1046-Q1 pin diagram , and Figure 4-2 shows the TCAN1046V-Q1 pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the TCAN1046-Q1/TCAN1046V-Q1 data sheet.
Figure 4-1 TCAN1046-Q1 Pin
Diagram
Figure 4-2 TCAN1046V-Q1 Pin DiagramFollowing are the assumptions of use and the device configuration assumed for the pin FMA in this section:
- VCC = 4.5 to 5.5V
- VIO (if applicable) = 1.7 to 5.5V
Table 4-2 Pin FMA for Device Pins Short-Circuited to
Ground
| Pin Name | Pin No. (TCAN1046-Q1) | Pin No. (TCAN1046V-Q1) | Description of Potential Failure Effect(s) | Failure Effect Class |
|---|---|---|---|---|
| TXD1 | 1 | 1 | CAN1 will enter dominant time out mode. Unable to transmit data to the CAN1 bus. | B |
| GND1 | 2 | 2 | None | D |
| VCC1 | 3 | - | CAN1 unpowered, high ICC current. | B |
| VCC | - | 3 | Device unpowered, high ICC current. | B |
| RXD1 | 4 | 4 | Internal damage possible, MCU may not be able to receive data from the RXD pin. Unable to receive data from CAN1 bus. | A |
| TXD2 | 5 | 6 | CAN2 will enter dominant time out mode. Unable to transmit data to the CAN2 bus. | B |
| GND2 | 6 | 5 | None | D |
| VCC2 | 7 | - | CAN2 unpowered, high ICC current. | B |
| RXD2 | 8 | 7 | Internal damage possible, MCU may not be able to receive data from the RXD pin. Unable to receive data from CAN2 bus. | A |
| CANL2 | 9 | 9 | VO(REC) spec violated. Degraded EMC performance on CAN2 bus. | C |
| CANH2 | 10 | 10 | Device cannot drive dominant to CAN2 bus, no communication possible. | B |
| STB2 | 11 | 8 | STB2 stuck low, CAN2 bus unable to enter low-power mode. | B |
| VIO | - | 11 | Device will be in protected mode. Transceiver passive on both CAN1 and CAN2 bus. | B |
| CANL1 | 12 | 12 | VO(REC) spec violated. Degraded EMC performance on CAN1 bus. | C |
| CANH1 | 13 | 13 | Device cannot drive dominant to CAN1 bus, no communication possible. | B |
| STB1 | 14 | 14 | STB1 stuck low, CAN1 bus unable to enter low-power mode. | B |
| Thermal Pad | - | - | None | D |
Table 4-3 Pin FMA for Device Pins Open-Circuited
| Pin Name | Pin No. (TCAN1046-Q1) | Pin No. (TCAN1046V-Q1) | Description of Potential Failure Effect(s) | Failure Effect Class |
|---|---|---|---|---|
| TXD1 | 1 | 1 | TXD1 pin defaults high, CAN1 bus state always recessive and unable to transmit data to CAN1 bus. | B |
| GND1 | 2 | 2 | CAN1 unpowered. | B |
| VCC1 | 3 | - | CAN1 unpowered. | B |
| VCC | - | 3 | Device unpowered. | B |
| RXD1 | 4 | 4 | No RXD1 output, unable to receive data from CAN1 bus. | B |
| TXD2 | 5 | 6 | TXD2 pin defaults high, CAN2 bus state always recessive and unable to transmit data to CAN2 bus. | B |
| GND2 | 6 | 5 | CAN2 unpowered. | B |
| VCC2 | 7 | - | CAN2 unpowered. | B |
| RXD2 | 8 | 7 | No RXD2 output, unable to receive data from CAN2 bus. | B |
| CANL2 | 9 | 9 | Device cannot drive dominant on CAN2 bus, unable to communicate. | B |
| CANH2 | 10 | 10 | Device cannot drive dominant on CAN2 bus, unable to communicate. | B |
| STB2 | 11 | 8 | STB2 pin defaults high, CAN2 portion stuck in low-power mode. | B |
| VIO | - | 11 | Device will be in protected mode, Transceiver passive on both CAN1 and CAN2 bus. | B |
| CANL1 | 12 | 12 | Device cannot drive dominant on CAN1 bus, unable to communicate. | B |
| CANH1 | 13 | 13 | Device cannot drive dominant on CAN1 bus, unable to communicate. | B |
| STB1 | 14 | 14 | STB1 pin defaults high, CAN1 portion stuck in low-power mode. | B |
| Thermal Pad | - | - | None | D |
Table 4-4 Pin FMA for Device Pins Short-Circuited to
Adjacent Pin TCAN1046-Q1
| Pin Name | Pin No. | Shorted to | Description of Potential Failure Effect(s) | Failure Effect Class |
|---|---|---|---|---|
| TXD1 | 1 | GND1 | CAN1 bus will enter dominant time out mode. Unable to transmit data to CAN1 bus. | B |
| GND1 | 2 | VCC1 | CAN1 unpowered, high ICC current. | B |
| VCC1 | 3 | RXD1 | RXD1 output stuck high, unable to receive data from CAN1 bus. | B |
| RXD1 | 4 | TXD2 | RXD1 output reflects the input to TXD2, a separate CAN transceiver. Information from CAN1 will not be received correctly. | B |
| TXD2 | 5 | GND2 | CAN2 bus will enter dominant time out mode. Unable to transmit data to CAN2 bus. | B |
| GND2 | 6 | VCC2 | CAN2 unpowered, high ICC current. | B |
| RXD2 | 8 | CANL2 | Messages on RXD2 will be corrupted by CANL2. Reception of data from CAN2 bus will not be possible. IOS current may be reached. | B |
| CANL2 | 9 | CANH2 | CAN2 bus stuck recessive, no communication possible. IOS current may be reached. | B |
| CANH2 | 10 | STB2 | CAN2 driver and receiver turn off when a dominant is driven on CAN2 bus. May not enter normal mode. | B |
| STB2 | 11 | CANL1 | CAN2 driver and receiver may turn off when the CAN1 bus is recessive. May not enter normal mode. | B |
| CANL1 | 12 | CANH1 | CAN1 bus stuck recessive, no communication possible IOS current may be reached. | B |
| CANH1 | 13 | STB1 | CAN1 driver and receiver turn off when a dominant is driven on CAN1 bus. 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.
Table 4-5 Pin FMA for Device Pins Short-Circuited to Adjacent Pin TCAN1046V-Q1
| Pin Name | Pin No. | Shorted to | Description of Potential Failure Effect(s) | Failure Effect Class |
|---|---|---|---|---|
| TXD1 | 1 | GND1 | CAN1 bus will enter dominant time out mode. Unable to transmit data to CAN1 bus. | B |
| GND1 | 2 | VCC | Device unpowered, high ICC current. | B |
| VCC | 3 | RXD1 | RXD1 output stuck high, unable to receive data from CAN1 bus. | B |
| RXD1 | 4 | GND2 | CAN1 receiver output stuck dominant. Unable to receive data from CAN1 bus. | B |
| GND2 | 5 | TXD2 | CAN2 bus will enter dominant time out mode. Unable to transmit data to CAN2 bus. | B |
| TXD2 | 6 | RXD2 | RXD2 output reflects the input to TXD2, and while this is the same transceiver, due to loop delay, the communication will be corrupted. Information from CAN2 bus will not be received correctly. | B |
| STB2 | 8 | CANL2 | CAN2 driver and receiver may turn off when the CAN2 bus is recessive. May not enter normal mode. | B |
| CANL2 | 9 | CANH2 | CAN2 bus stuck recessive, no communication possible. IOS current may be reached. | B |
| CANH2 | 10 | VIO | CAN2 bus stuck dominant, no communication possible. | B |
| VIO | 11 | CANL1 | CAN1 bus stuck recessive, no communication possible. IOS current may be reached on CANL1. | B |
| CANL1 | 12 | CANH1 | CAN1 bus stuck recessive, no communication possible IOS current may be reached. | B |
| CANH1 | 13 | STB1 | CAN1 driver and receiver turn off when a dominant is driven. May not enter normal mode. | B |
Table 4-6 Pin FMA for Device Pins Short-Circuited to
VCC
| Pin Name | Pin No. (TCAN1046-Q1) | Pin No. (TCAN1046V-Q1) | Description of Potential Failure Effect(s) | Failure Effect Class |
|---|---|---|---|---|
| TXD1 | 1 | 1 | TXD1 pin stuck high, unable to transmit data to CAN1 bus. | B |
| GND1 | 2 | 2 | CAN1 transceiver unpowered, high ICC current. | B |
| VCC1 | 3 | - | None | D |
| VCC | - | 3 | None | D |
| RXD1 | 4 | 4 | RXD1 pin stuck high, unable to receive data from CAN1 bus. | B |
| TXD2 | 5 | 6 | TXD2 pin stuck high, unable to transmit data to CAN2 bus. | B |
| GND2 | 6 | 5 | CAN2 transceiver unpowered, high ICC current. | B |
| VCC2 | 7 | - | None | D |
| RXD2 | 8 | 7 | RXD2 pin stuck high, unable to receive data for CAN2 bus. | B |
| CANL2 | 9 | 9 | CAN2 bus always recessive, no communication possible. IOS current may be reached. | B |
| CANH2 | 10 | 10 | VO(REC) spec violated, degraded EMC performance on CAN2 bus. | C |
| STB2 | 11 | 8 | STB2 stuck high, CAN2 transceiver always in standby mode. | B |
| VIO | - | 11 | IO pins will operate as 5V input/output. Microcontroller may be damaged if VCC > VIO. | C |
| CANL1 | 12 | 12 | CAN1 bus always recessive, no communication possible. IOS current may be reached. | B |
| CANH1 | 13 | 13 | VO(REC) spec violated, degraded EMC performance on CAN1 bus. | C |
| STB1 | 14 | 14 | STB1 stuck high, CAN1 transceiver always in standby mode. |
Table 4-7 PIN FMA for Device Pins Short-Circuited to VIO
| Pin Name | Pin No. (TCAN1046V-Q1) | Description of Potential Failure Effect(s) | Failure Effect Class |
|---|---|---|---|
| TXD1 | 1 | TXD1 stuck high, unable to transmit data to CAN1 bus. | B |
| GND1 | 2 | CAN1 unpowered, high IIO current. | B |
| VCC | 3 | IO pins will operate as 5V input/output. Microcontroller may be damaged if VCC > VIO. | C |
| RXD1 | 4 | RXD1 pin stuck high, unable to receive data from CAN1 bus. | B |
| GND2 | 5 | CAN2 unpowered, high IIO current. | B |
| TXD2 | 6 | TXD2 stuck high, unable to transmit data to CAN2 bus. | B |
| RXD2 | 7 | RXD2 pin stuck high, unable to receive data from CAN2 bus. | B |
| STB2 | 8 | STB2 stuck high, CAN2 transceiver always in standby mode. | B |
| CANL2 | 9 | CAN2 bus always recessive, no communication possible. IOS current may be reached if VIO ≥ 3.3V. | B |
| CANH2 | 10 | VO(REC) spec violated if VIO ≥ 3.3V, degraded EMC performance on CAN2 bus. | C |
| VIO | 11 | None | D |
| CANL1 | 12 | CAN1 bus always recessive, no communication possible. IOS current may be reached if VIO ≥ 3.3V. | B |
| CANH1 | 13 | VO(REC) spec violated if VIO ≥ 3.3V, degraded EMC performance on CAN1 bus. | C |
| STB1 | 14 | STB1 stuck high, CAN1 transceiver always in standby mode. | B |
Table 4-8 Pin FMA for Device Pins Short-Circuited to VBAT
| Pin Name | Pin No. (TCAN1046-Q1) | Pin No. (TCAN1046V-Q1) | Description of Potential Failure Effect(s) | Failure Effect Class |
|---|---|---|---|---|
| TXD1 | 1 | 1 | Absolute maximum violation, transceiver may be damaged. Unable to transmit data to CAN1 bus. | A |
| GND1 | 2 | 2 | Device unpowered, high IBAT current. | B |
| VCC1 | 3 | - | Absolute maximum violation, transceiver may be damaged. CAN1 bus may be unable to communicate. | A |
| VCC | - | 3 | Absolute maximum violation, transceiver may be damaged. CAN bus may be unable to communicate. | A |
| RXD1 | 4 | 4 | Absolute maximum violation, transceiver may be damaged. Unable to receive data from CAN1 bus. | A |
| TXD2 | 5 | 6 | Absolute maximum violation, transceiver may be damaged. Unable to transmit data to CAN2 bus. | A |
| GND2 | 6 | 5 | Device unpowered, high IBAT current. | B |
| VCC2 | 7 | - | Absolute maximum violation, transceiver may be damaged. CAN2 bus may be unable to communicate. | A |
| RXD2 | 8 | 7 | Absolute maximum violation, transceiver may be damaged. Unable to receive data from CAN2 bus. | B |
| CANL2 | 9 | 9 | CAN2 bus always recessive, no communication possible. IOS current may be reached. | B |
| CANH2 | 10 | 10 | VO(REC) spec violated, degraded EMC performance on CAN2 bus. | C |
| STB2 | 11 | 8 | Absolute maximum violation, transceiver may be damaged. CAN2 transceiver stuck in standby mode. | A |
| VIO | - | 11 | Absolute maximum violation, transceiver may be damaged. | A |
| CANL1 | 12 | 12 | CAN1 bus always recessive, no communication possible. IOS current may be reached. | B |
| CANH1 | 13 | 13 | VO(REC) spec violated, degraded EMC performance on CAN1 bus. | B |
| STB1 | 14 | 14 | Absolute maximum violation, transceiver may be damaged. CAN1 transceiver stuck in standby mode. | A |
