FUNCTIONAL SAFETY FIT RATE, FMD AND PIN-FMA
TCAN1043A-Q1 Functional Safety FIT Rate, FMD, and Pin FMA
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1 Overview
This document contains information for TCAN1043A-Q1. This is a Controller Area Network (CAN) transceiver in the SOIC (D), VSON (DMT), and SOT (DYY) packages 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 (FMA) for the device pins of TCAN1043A-Q1
Figure 1-1 shows the device functional block diagram for reference.
Figure 1-1 TCAN1043A-Q1 Functional Block
Diagram2 Functional Safety Failure In Time (FIT) Rates
This section provides Functional Safety Failure In Time (FIT) rates for TCAN1043A-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 SOIC (D) | FIT (Failures Per 109 Hours) 14-pin VSON (DMT) | FIT (Failures Per 109 Hours) 14-pin SOT (DYY) |
|---|---|---|---|
| Total Component FIT Rate | 22 | 10 | 11 |
| Die FIT Rate | 6 | 4 | 7 |
| Package FIT Rate | 16 | 6 | 4 |
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: 353 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 ASICs Analog & Mixed ≤ 50 V supply | 25 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 TCAN1043A-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 | 35% |
| Transmitter Fail | 35% |
| System stuck in sleep mode | 15% |
| Control and Mode logic failure | 10% |
| CANL or CANH driver stuck dominant | 5% |
4 Pin Failure Mode Analysis (Pin FMA)
This section provides a Failure Mode Analysis (FMA) for the pins of the TCAN1043A-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 VSUP (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.
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 TCAN1043A-Q1 SOIC pin diagram. Figure 4-2 shows the TCAN1043A-Q11 VSON pin diagram. Figure 4-3 shows the TCAN1043A-Q1 SOT pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the TCAN1043A-Q1 data sheet.
Figure 4-1 SOIC Pin Diagram
Figure 4-2 VSON Pin Diagram
Figure 4-3 SOT
Pin Diagram
Following are the assumptions of use and the device configuration assumed for the pin FMA in this section:
- VCC = 4.5 V to 5.5 V
- VSUP = 4.5 V to 40 V
- VIO = 1.7 V to 5.5 V
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 |
|---|---|---|---|
| TXD | 1 | TXD is biased dominant indefinitely and device enters dominant time out mode. Unable to transmit data. | B |
| GND | 2 | None | D |
| VCC | 3 | Device is in protected mode, The high current draw from external regulator supplying VCC. | B |
| RXD | 4 | Receiver output biased recessive indefinitely. The host is unable to receive data from bus. | B |
| VIO | 5 | Device is in protected mode. Transceiver passive on bus, and high current draw from external regulator supplying VIO. | B |
| EN | 6 | EN pin biased low, device is not able to enter normal mode. Unable to communicate. | B |
| INH | 7 | High ISUP current, INH pin may be damaged, and indication from sleep mode transition not available. | A |
| nFAULT | 8 | nFAULT pin biased low indefinitely which indicates a fault indefinitely. | B |
| WAKE | 9 | WAKE pin biased low indefinitely, is not able to utilize local wake-up function. | B |
| VSUP | 10 | Device unpowered, high ISUP current. | B |
| NC | 11 | None | D |
| CANL | 12 | VO(REC) spec violated. Degraded EMC performance. | C |
| CANH | 13 | Device cannot drive dominant to the bus, no communication possible. | B |
| nSTB | 14 | nSTB biased low indefinitely. The transceiver unable to enter normal mode. Unable to communicate. | 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 Effect(s) | Failure Effect Class |
|---|---|---|---|
| TXD | 1 | TXD pin defaults to a recessive bias, device is always recessive and unable to transmit data. | B |
| GND | 2 | Device unpowered. | B |
| VCC | 3 | Device in protected mode. | B |
| RXD | 4 | No RXD output, unable to receive data. | B |
| VIO | 5 | Device in protected mode. | B |
| EN | 6 | EN pin defaults to a logic-low bias, device is not able to enter normal mode. Unable to communicate. | B |
| INH | 7 | None | D |
| nFAULT | 8 | No effect on performance, unable to monitor system faults. | B |
| WAKE | 9 | No effect on device performance, is not able to use local wake-up function. | B |
| VSUP | 10 | Device unpowered. | B |
| NC | 11 | None | D |
| CANL | 12 | Device cannot drive dominant on bus, and is unable to communicate. | B |
| CANH | 13 | Device cannot drive dominant on bus, and is unable to communicate. | B |
| nSTB | 14 | nSTB defaults to a logic-low bias, device is not able to enter normal mode. Unable to communicate. | 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 Effect(s) | Failure Effect Class |
|---|---|---|---|---|
| TXD | 1 | GND | TXD will be biased dominant indefinitely and device will enter dominant time out mode. Unable to transmit data. | B |
| GND | 2 | VCC | Device will be in protected mode, high ICC current. | B |
| VCC | 3 | RXD | RXD output biased recessive indefinitely, controller unable to receive data from CAN bus. | B |
| RXD | 4 | VIO | RXD output biased recessive indefinitely, controller unable to receive data from CAN bus. | B |
| VIO | 5 | EN | EN pin biased high indefinitely, device is unable to enter standby and silent mode. | B |
| EN | 6 | INH | Absolute maximum violation on EN pin except in sleep mode. Transceiver may be damaged. | A |
| nFAULT | 8 | WAKE | Potential absolute maximum violation on nFAULT pin if WAKE is biased high. Transceiver may be damaged. | A |
| WAKE | 9 | VSUP | WAKE biased high indefinitely, unable to utilize local wake-up function. | B |
| VSUP | 10 | NC | None | D |
| NC | 11 | CANL | None | D |
| CANL | 12 | CANH | Bus biased recessive, no communication possible. IOS current may be reached on CANH/CANL. | B |
| CANH | 13 | nSTB | Driver and receiver turn off when the CAN bus is recessive. 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 VCC
| Pin Name | Pin No. | Description of Potential Failure Effect(s) | Failure Effect Class |
|---|---|---|---|
| TXD | 1 | TXD biased recessive indefinitely, unable to transmit data. | B |
| GND | 2 | Device unpowered, high current draw from external regulator supplying VCC. | B |
| VCC | 3 | None | D |
| RXD | 4 | Receiver output biased recessive indefinitely. Host unable to receive data from bus. | B |
| VIO | 5 | IO pins will operate as 5 V input/outputs. Microcontroller may be damaged if VCC > VIO. | C |
| EN | 6 | EN biased high indefinitely, device are unable to enter standby and silent mode. | B |
| INH | 7 | Absolute maximum violation on VCC pin, INH is biased at VCC voltage, system may not wake up. | B |
| nFAULT | 8 | nFAULT biased high indefinitely, transceiver unable to report faults. | B |
| WAKE | 9 | None | D |
| VSUP | 10 | Absolute maximum violation on VCC. | B |
| NC | 11 | None | D |
| CANL | 12 | IOS current may be reached, RXD always recessive. | B |
| CANH | 13 | VO(REC) spec violated, degraded EMC performance. | C |
| nSTB | 14 | nSTB biased high indefinitely, transceiver unable to enter standby and sleep mode. | B |
Table 4-6 Pin FMA for Device Pins Short-Circuited to VSUP
| Pin Name | Pin No. | Description of Potential Failure Effect(s) | Failure Effect Class |
|---|---|---|---|
| TXD | 1 | Absolute maximum violation, transceiver may be damaged. | A |
| GND | 2 | Device unpowered, high ISUP current. | B |
| VCC | 3 | Absolute maximum violation, transceiver may be damaged. | A |
| RXD | 4 | Absolute maximum violation, transceiver may be damaged. | A |
| VIO | 5 | Absolute maximum violation, transceiver may be damaged. | A |
| EN | 6 | Absolute maximum violation, transceiver may be damaged. | A |
| INH | 7 | Minimal current driven into the INH pin. | D |
| nFAULT | 8 | Absolute maximum violation, transceiver may be damaged. | A |
| WAKE | 9 | WAKE biased high, unable to use local wake-up function. | B |
| VSUP | 10 | None | D |
| NC | 11 | None | D |
| CANL | 12 | IOS current may be reached. RXD always recessive. | B |
| CANH | 13 | VO(REC) spec violated, degraded EMC performance and communcation errors may result as well. | C |
| nSTB | 14 | Absolute maximum violation, transceiver may be damaged. | A |
Table 4-7 Pin
FMA for Device Pins Short-Circuited to
VIO
| Pin Name | Pin No. | Description of Potential Failure Effect(s) | Failure Effect Class |
|---|---|---|---|
| TXD | 1 | TXD biased recessive indefinitely, unable to transmit data. | B |
| GND | 2 | Device unpowered, high current draw from external regulator supplying VIO. | B |
| VCC | 3 | IO pins will operate as 5 V input/outputs. Microcontroller may be damaged if VCC > VIO. | C |
| RXD | 4 | Receiver output biased recessive indefinitely. Host unable to receive data from bus. | B |
| VIO | 5 | None | D |
| EN | 6 | EN biased high indefinitelyf, device are unable to enter standby and silent mode. | B |
| INH | 7 | Absolute maximum violation on VIO pin, INH is biased at VIO voltage, system may not wake up. | B |
| nFAULT | 8 | nFAULT biased high indefinitely, transceiver unable to report faults. | B |
| WAKE | 9 | None | D |
| VSUP | 10 | Absolute maximum violation on VIO. | B |
| NC | 11 | None | D |
| CANL | 12 | IOS current may be reached, RXD always recessive. | B |
| CANH | 13 | VO(REC) spec violated, degraded EMC performance. | C |
| nSTB | 14 | nSTB biased high indefinitely, transceiver unable to enter standby and sleep mode. | B |
Note: Table 4-7 is only applicable to the TCAN1043A-Q1 device.
5 Revision History
| DATE | REVISION | NOTES |
|---|---|---|
| * | Initial Release |
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