SFFS096 October 2021 TCAN1043A-Q1

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 V_CC (see Table 4-5)
Pin short-circuited to V_SUP (see Table 4-6)
Pin short-circuited to V_IO (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:

V_CC = 4.5 V to 5.5 V
V_SUP = 4.5 V to 40 V
V_IO = 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
V_CC	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
V_IO	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 I_SUP 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
V_SUP	10	Device unpowered, high I_SUP current.	B
NC	11	None	D
CANL	12	V_O(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
V_CC	3	Device in protected mode.	B
RXD	4	No RXD output, unable to receive data.	B
V_IO	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
V_SUP	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 I_CC current.	B
V_CC	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
V_SUP	10	NC	None	D
NC	11	CANL	None	D
CANL	12	CANH	Bus biased recessive, no communication possible. I_OS 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 V_CC

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
V_CC	3	None	D
RXD	4	Receiver output biased recessive indefinitely. Host unable to receive data from bus.	B
V_IO	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
V_SUP	10	Absolute maximum violation on VCC.	B
NC	11	None	D
CANL	12	I_OS current may be reached, RXD always recessive.	B
CANH	13	V_O(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 V_SUP

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 I_SUP current.	B
V_CC	3	Absolute maximum violation, transceiver may be damaged.	A
RXD	4	Absolute maximum violation, transceiver may be damaged.	A
V_IO	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
V_SUP	10	None	D
NC	11	None	D
CANL	12	I_OS current may be reached. RXD always recessive.	B
CANH	13	V_O(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 V_IO

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
V_CC	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
V_IO	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
V_SUP	10	Absolute maximum violation on VIO.	B
NC	11	None	D
CANL	12	I_OS current may be reached, RXD always recessive.	B
CANH	13	V_O(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.