SFFS570 January   2025 ISOUSB211

 

  1.   1
  2.   Trademarks
  3. 1Overview
  4. 2Functional Safety Failure In Time (FIT) Rates
  5. 3Failure Mode Distribution (FMD)
  6. 4Pin Failure Mode Analysis (Pin FMA)
  7. 5Revision History

4 Pin Failure Mode Analysis (Pin FMA)

This section provides a failure mode analysis (FMA) for the pins of the ISOUSB211 (DP-28 package). 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 supply (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
ClassFailure Effects
APotential device damage that affects functionality.
BNo device damage, but loss of functionality.
CNo device damage, but performance degradation.
DNo device damage, no impact to functionality or performance.

Figure 4-1 shows the ISOUSB211 pin diagram. For a detailed description of the device pins, see the Pin Configuration and Functions section in the ISOUSB211 data sheet.

ISOUSB211 Pin Diagram Figure 4-1 Pin Diagram
Table 4-2 Pin FMA for Device Pins Short-Circuited to Ground
Pin Name Pin No. Description of Potential Failure Effects Failure Effect Class
VBUS1 1 No power to the device on side one. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. A
V3P3V1 2 No power to the device on side one. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. A
GND1 3 Device continues to function as expected. Normal operation. D
V1P8V1 4 No power to the high-speed device on side one. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. A
VCC1 5 No power to the high-speed device on side one. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. A
V2OK 6 Loss of the indication of the power condition of side two. A
UD- 7 Upstream facing port D- is shorted to ground. Loss of signal communication. B
UD+ 8 Upstream facing port D+ is shorted to ground. Loss of signal communication. B
EQ10 9 EQ10 stuck low. Cannot set the EQ10 for higher equalization. C
EQ11 10 EQ11 stuck low. Cannot set the EQ11 for higher equalization. C
V1P8V1 11 No power to the high-speed device on side one. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. A
GND1 12 Device continues to function as expected. Normal operation. D
CDPENZ1 13 Charging downstream port (CDP) is advertized through the UD+ and UD- pins. B
NC 14 Device continues to function as expected. Normal operation. D
NC 15 Device continues to function as expected. Normal operation. D
CDPENZ2 16 Charging downstream port (CDP) is advertized through the DD+ and DD- pins. B
GND2 17 Device continues to function as expected. Normal operation. D
V1P8V2 18 No power to the high-speed device on side two. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. A
EQ21 19 EQ20 stuck low. Cannot set the EQ20 for higher equalization. C
EQ20 20 EQ21 stuck low. Cannot set the EQ21 for higher equalization. C
DD+ 21 Downstream facing port D+ is shorted to ground. Loss of signal communication. B
DD- 22 Downstream facing port D- is shorted to ground. Loss of signal communication. B
V1OK 23 Loss of the indication that side one is powered up. A
VCC2 24 No power to the high-speed device on side two. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. A
V1P8V2 25 No power to the high-speed device on side two. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. A
GND2 26 Device continues to function as expected. Normal operation. D
V3P3V2 27 No power to the high-speed device on side two. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. A
VBUS2 28 No power to the high-speed device on side two. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. A
Table 4-3 Pin FMA for Device Pins Open-Circuited
Pin Name Pin No. Description of Potential Failure Effects Failure Effect Class
VBUS1 1 VBUS1 has no power supply.
If V3P3V1 connects to a power supply, the internal LDO can be damaged from the reverse current.
If V3P3V1 does not connect to a power supply, observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible.		 A
V3P3V1 2 If VBUS1 connects to a power supply ≥ 4.25V, the internal LDO is functioning and providing 3.3V to the circuitry. However, the 3.3V voltage output can have stability issues without proper external bypass capacitors.
If VBUS1 does not connect to a power supply, observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. 		A
GND1 3 Device continues to function as expected with potential degraded performance with pin 12 as GND1. C
V1P8V1 4 Device continues to function as expected as pin 11 is functioning as the V1P8V1. Normal operation. B
VCC1 5 VCC1 has no power supply.
If V1P8V1 connects to a power supply, the internal LDO can be damaged from the reverse current.
If V1P8V1 does not connect to a power supply, observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible.		 A
V2OK 6 Loss of the indication of the power condition of side two. D
UD- 7 Upstream facing port D- is floating. Loss of signal communication. B
UD+ 8 Upstream facing port D+ is floating. Loss of signal communication. B
EQ10 9 EQ10 is floating. Cannot adjust the EQ10. C
EQ11 10 EQ11 is floating. Cannot adjust the EQ11. C
V1P8V1 11 Device continues to function as expected as pin 4 is functioning as the V1P8V1. Normal operation. B
GND1 12 Device continues to function as expected with potential degraded performance with pin 3 as GND1. C
CDPENZ1 13 Loss of the ability to advertize CDP on the UD+ and UD- pins. B
NC 14 Device continues to function as expected. Normal operation. D
NC 15 Device continues to function as expected. Normal operation. D
CDPENZ2 16 Loss of the ability to advertize CDP on the DD+ and DD- pins. B
GND2 17 Device continues to function as expected with potential degraded performance with pin 26 as GND2. C
V1P8V2 18 Device continues to function as expected as pin 25 is functioning as the V1P8V1. Normal operation. B
EQ21 19 EQ21 is floating. Cannot adjust the EQ21. C
EQ20 20 EQ20 is floating. Cannot adjust the EQ20. C
DD+ 21 Downstream facing port D- is floating. Loss of signal communication. B
DD- 22 Downstream facing port D+ is floating. Loss of signal communication. B
V1OK 23 Loss of the indication of the power condition of side one. D
VCC2 24 VCC2 has no power supply.
If V1P8V2 connects to a power supply, the internal LDO can be damaged from the reverse current.
If V1P8V2 does not connect to a power supply, observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible.		 A
V1P8V2 25 No power to the high-speed device on side two. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. OUTD state is undetermined. B
GND2 26 Device continues to function as expected with potential degraded performance with pin 17 as GND2. C
V3P3V2 27 No power to the high-speed device on side two. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. OUTD state is undetermined. A
VBUS2 28 No power to the high-speed device on side two. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. OUTD state is undetermined. A
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
VBUS1 1 V3P3V1 If VBUS1 is connected to a power supply > 4.25V, the supply input exceeds the V3P3V1 absolute maximum rating and damage to the device is plausible. A
V3P3V1 2 GND1 No power to the device on side one. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. A
GND1 3 V1P8V1 No power to the device on side one. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. A
V1P8V1 4 VCC1 If VCC1 is connected to a power supply > 2.1V, the supply input exceeds the V1P8V1 absolute maximum rating and damage to the device is plausible. A
VCC1 5 V2OK V2OK is stuck high. A
V2OK 6 UD- Loss of information for V2OK and UD-. A
UD- 7 UD+ Loss of information for UD- and UD+. B
UD+ 8 EQ10 Loss of information for UD+ and EQ10. B
EQ10 9 EQ11 EQ10 and QE11 are set to the same logic state. C
EQ11 10 V1P8V1 EQ11 is set to 1.8V. EQ11 setting is undetermined. C
V1P8V1 11 GND1 No power to the device on side one. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. A
GND1 12 CDPENZ1 Loss of the ability to advertize CDP on the UD+ and UD- pins. B
CDPENZ1 13 NC Device continues to function as expected. Normal operation. D
NC 14 CDPENZ1 Device continues to function as expected. Normal operation. D
NC 15 CDPENZ2 Device continues to function as expected. Normal operation. D
CDPENZ2 16 NC Device continues to function as expected. Normal operation. D
GND2 17 CDPENZ2 Loss of the ability to advertize CDP on the DD+ and DD- pins. B
V1P8V2 18 GND2 No power to the device on side two. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. A
EQ21 19 V1P8V2 EQ21 is set to 1.8V. EQ21 setting is undetermined. C
EQ20 20 EQ21 EQ20 and QE21 are set to the same logic state. C
DD+ 21 EQ20 Loss of information for DD+ and EQ20. B
DD- 22 DD+ Loss of information for DD- and DD+. B
V1OK 23 DD- Loss of information for V2OK and DD-. A
VCC2 24 V1OK V1OK is stuck high. A
V1P8V2 25 VCC2 If VCC2 is connected to a power supply > 2.1V, the supply input exceeds the V1P8V2 absolute maximum rating and damage to the device is plausible. A
GND2 26 V1P8V2 No power to the device on side two. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. A
V3P3V2 27 GND2 No power to the device on side two. Observe that the absolute maximum ratings for all pins of the device are met; otherwise device damage is plausible. A
VBUS2 28 V3P3V2 If VBUS2 is connected to a power supply > 4.25V, the supply input exceeds the V3P3V2 absolute maximum rating and damage to the device is plausible. A
Table 4-5 Pin FMA for Device Pins Short-Circuited to Supply
Pin Name Pin No. Description of Potential Failure Effects Failure Effect Class
VBUS1 1 Device continues to function as expected. Normal operation. D
V3P3V1 2 When shorted to the 5V supply, the supply input of the V3P3V1 pin exceeds the absolute maximum rating of 4.25V and damage to the device is plausible. A
GND1 3 Can create potential difference between pin 3 and pin 12 causing high current to flow in the device; damage to the device is plausible. A
V1P8V1 4 When shorted to the 5V supply, the supply input of the V1P8V1 pin exceeds the absolute maximum rating of 2.1V and damage to the device is plausible. A
VCC1 5 Device continues to function as expected. Normal operation. D
V2OK 6 V2OK is stuck high. Loss of the indication of the power condition of side two. A
UD- 7 Upstream facing port D- stuck high. Lost of signal communication. B
UD+ 8 Upstream facing port D+ is stuck high. Loss of signal communication. B
EQ10 9 EQ10 is stuck high. Cannot adjust the EQ10. C
EQ11 10 EQ11 is stuck high. Cannot adjust the EQ11. C
V1P8V1 11 When shorted to the 5V, the supply input of the V1P8V1 pin exceeds the absolute maximum rating of 2.1V and damage to the device is plausible. A
GND1 12 Can create potential difference between pin 3 and pin 12 causing high current to flow in the device; damage to the device is plausible. A
CDPENZ1 13 CDPENZ1 is stuck high. Loss of the ability to advertize CDP on the UD+ and UD- pins. B
NC 14 Device continues to function as expected. Normal operation. D
NC 15 Device continues to function as expected. Normal operation. D
CDPENZ2 16 CDPENZ2 is stuck high. Loss of the ability to advertize CDP on the DD+ and DD- pins. B
GND2 17 Can create potential difference between pin 17 and pin 26 causing high current to flow in the device; damage to the device is plausible. A
V1P8V2 18 When shorted to the 5V, the supply input of the V1P8V2 pin exceeds the absolute maximum rating of 2.1V and damage to the device is plausible. A
EQ21 19 EQ21 is stuck high. Cannot adjust the EQ21. C
EQ20 20 EQ20 is stuck high. Cannot adjust the EQ20. C
DD+ 21 Downstream facing port D- is stuck high. Loss of signal communication. B
DD- 22 Downstream facing port D+ is stuck high. Loss of signal communication. B
V1OK 23 V1OK is stuck high. Loss of the indication of the power condition of side one. A
VCC2 24 Device continues to function as expected. Normal operation. D
V1P8V2 25 When shorted to the 5V, the supply input of the V1P8V2 pin exceeds the absolute maximum rating of 2.1V and damage to the device is plausible. A
GND2 26 Can create potential difference between pin 17 and pin 26 causing high current to flow in the device; damage to the device is plausible. A
V3P3V2 27 When shorted to the 5V, the supply input of the V3P3V2 pin exceeds the absolute maximum rating of 4.25V and damage to the device is plausible. A
VBUS2 28 Device continues to function as expected. Normal operation. D