SLVAEV0A July   2020  – July 2022 TPS25833-Q1

 

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

4 Pin Failure Mode Analysis (Pin FMA)

This section provides a failure mode analysis (FMA) for the pins of the TPS25833-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 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
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 and Figure 4-2 show the TPS25833-Q1 pin diagram. For a detailed description of the device pins, see the Pin Configuration and Functions section in the TPS25833-Q1 data sheet.

GUID-20210719-CA0I-ZMDV-LD7C-9B23W7ZBZLD6-low.gif Figure 4-1 TPS25833QCWRHBRQ1 Pin Diagram
GUID-A921DCE6-4824-4B8E-9BC1-B6DF8C2E9480-low.gif Figure 4-2 TPS25833QWRHBRQ1 Pin Diagram

Following are the assumptions of use and the device configuration assumed for the pin FMA in this section:

  • Device used within the 'Recommended Operating Conditions' and the 'Absolute Maximum Ratings' found in the appropriate device data sheet.

  • Configuration as shown in the 'Example Application Circuit' found in the appropriate device data sheet.

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
VIN 1 Device does not operate. No output voltage is generated. B
VIN 2 Device does not operate. No output voltage is generated. B
VIN 3 Device does not operate. No output voltage is generated. B
EN 4 Loss of ENABLE functionality. Device remains in shutdown mode. B
CTRL1 5 Device stays at reserved mode or DCP auto mode. When in the reserved mode, the output charging is abnormal. B
CTRL2 6 Device stay at reserved mode or SDP mode. When in the reserved mode, the output charging is abnormal. B
/THERM_WARN 7 Loss of THERM_WARN functionality. Device always appears to be in the thermal warning condition. C
NTC 8 Loss of Temperature Sense functionality. Device cannot sense the external PCB temperature. C
RT/SYNC 9 Device internal buck switching frequency goes up to 4.6 MHz, and the CSN pin voltage up to 7 V. It makes the output charging. B
LS_GD 10 Device cannot drive external FET for current limit. B
IMON 11 Loss of Cable Compensation functionality. Device cannot make a cable compensation. C
ILIMT 12 Loss of Current Limit functionality. Device uses the maximum current limit value of 3.5 A. C
CSN/OUT 13 Device internal buck output short circuits. Device enters hiccup mode. B
CSP 14 Device internal buck output short circuits. Device enters hiccup mode. B
BUS 15 Device hiccups and output current limit does work. B
AGND 16 No effect D
DM_IN 17 Device cannot support SDP/CDP/DCP auto charging mode. B
DP_IN 18 Device cannot support SDP/CDP/DCP auto charging mode. B
CC2 19 Device hiccups and output voltage is abnormal. B
CC1 20 Device hiccups and output voltage is abnormal. B
VCC 21 Device hiccups and cannot be powered on. B
/POL 22 Loss of /POL functionality. Device always appears to the CC2 pin is connected to the CC line in the cable. C
/LD_DET 23 Loss of /LD_DET functionality. Device always appears to a Type-C UFP is identified on the CC lines. C
/FAULT 24 Loss of /FAULT functionality. Device always appears to be in the fault condition. C
PGND 25 No effect D
PGND 26 No effect D
PGND 27 No effect D
SW 28 Device internal buck hiccup. Long-term reliability can impact. A
SW 29 Device internal buck hiccup. Long-term reliability can impact. A
SW 30 Device internal buck hiccup. Long-term reliability can impact. A
SW 31 Device internal buck hiccup. Long-term reliability can impact. A
BOOT 32 Device internal buck stop switching. No output voltage in VSN/OUT. B
Thermal Pad — No effect D
Table 4-3 Pin FMA for Device Pins Open-Circuited
Pin Name Pin No. Description of Potential Failure Effect(s) Failure Effect Class
VIN 1 Long-term reliability can impact due to lower bonding-wire count. C
VIN 2 Long-term reliability can impact due to lower bonding-wire count. C
VIN 3 Long-term reliability can impact due to lower bonding-wire count. C
EN 4 Device off and on cannot be controlled and is off and on depending on how EN floats. B
CTRL1 5 Device DCP auto/SDP/CDP/RESERVED mode cannot be controlled, and is DCP auto/SDP/CDP/RESERVED mode depending on how CTRL1 floats. B
CTRL2 6 Device DCP auto/SDP/CDP/RESERVED mode cannot be controlled, and is DCP auto/SDP/CDP/RESERVED mode depending on how CTRL2 floats. B
/THERM_WARN 7 Loss of THERM_WARN functionality. Device cannot be determined whether it is in the overtemperature condition. C
NTC 8 Device overtemperature or not cannot be controlled, and is depending on how NTC floats. C
RT/SYNC 9 Device internal buck switching frequency drop and loading current are limited to about a small value. This fact causes abnormal charging. B
LS_GD 10 Device cannot drive external FET for current limit. B
IMON 11 VOUT/CSN goes up to 6.9 V. This action can cause VBUS voltage over compensation and fail at the BC1.2 certification test. B
ILIMT 12 Device internal buck hiccups. B
CSN/OUT 13 Device internal buck output voltage is abnormal. B
CSP 14 Device cannot sense the output current signal. The output current limit and VBUS cable compensation don not work. C
BUS 15 Loss of VBUS OVP functionality. IEC ESD test is impacted. B
AGND 16 The device tries to power up by forward-biasing the ESD diode from the GND to another pin. Strange results are observed. B
DM_IN 17 Device cannot support SDP/CDP/DCP auto charging mode. B
DP_IN 18 Device cannot support SDP/CDP/DCP auto charging mode. B
CC2 19 Device Nothing attached/UFP connected/No UFP connected cannot be controlled. It depends on the state of CC1. B
CC1 20 Device Nothing attached/UFP connected/No UFP connected cannot be controlled. It depends on the state of CC2. B
VCC 21 Device cannot start up. Internal buck stops switching. B
/POL 22 Loss of /POL functionality, cannot give cable orientation information. C
/LD_DET 23 Loss of /LD_DET functionality. Cannot identify the Type-C UFP. C
/FAULT 24 Loss of /FAULT functionality, cannot check whether the device is in the fault condition. C
PGND 25 Long-term reliability can impact due to lower bonding-wire count. C
PGND 26 Long-term reliability can impact due to lower bonding-wire count. C
PGND 27 Long-term reliability can impact due to lower bonding-wire count. C
SW 28 Long-term reliability can impact due to lower bonding-wire count. C
SW 29 Long-term reliability can impact due to lower bonding-wire count. C
SW 30 Long-term reliability can impact due to lower bonding-wire count. C
SW 31 Long-term reliability can impact due to lower bonding-wire count. C
BOOT 32 Device internal buck HS FET cannot be turned on. VSN/OUT cannot get up to target voltage. B
Thermal Pad — Long-term reliability can impact if the device operates beyond the rate junction temperature for extended time because a heat path is interrupted. C
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
VIN 1 VIN No effect D
VIN 2 VIN No effect D
VIN 3 EN Device is enabled and cannot be disabled. D
EN 4 CTRL1 Device DCP auto/SDP/CDP/reserve mode and enable/disable cannot be controlled. It is DCP auto/SDP/CDP/ reserve mode and enable/disable depending on how EN and CTRL1 circuits interact. B
CTRL1 5 CTRL2 Device DCP auto/SDP/CDP/Reserve mode cannot be controlled. It is DCP auto/SDP/CDP/Reserve mode depending on how CTRL1 and CTRL2 circuits interact. B
CTRL2 6 /THERM_WARN Device DCP auto/SDP/CDP/Reserve mode cannot be controlled. It is DCP auto/SDP/CDP/Reserve mode depending on how CTRL2 and /THERM_WARN circuits interact. B
/THERM_WARN 7 NTC The NTC thermal sensing does not work, THERM_WARN flag and charging state do not report correctly. B
NTC 8 RT/SYNC Device internal buck switching is interrupted by NTC. B
RT/SYNC 9 LS_GD The LS_GD goes down from 11.3 V to 0.5 V, and the internal buck switching frequency is abnormal. Device cannot drive the external FET for current limit B
LS_GD 10 IMON LS_GD voltage set low, device cannot drive the external FET for current limit. B
IMON 11 ILIMT Current limit threshold and cable compensation value are impacted. C
ILIMT 12 CSN/OUT Ilimit is pulled up over 1 V, device behaves as average current limit and keeps hiccup. B
CSN/OUT 13 CSP Average current limit, external FET current limit and cable compensation function are bypassed. C
CSP 14 BUS Average current limit, external FET current limit and cable compensation function are bypassed. C
BUS 15 AGND Device goes into hiccup mode. B
AGND 16 DM_IN Device cannot support SDP/CDP/DCP auto charging mode. B
DM_IN 17 DP_IN Device only supports BC1.2 DCP mode. C
DP_IN 18 CC2 If shorted before charging, the device cannot charge. If shorted after charge, no effect. B
CC2 19 CC1 Pin short before power up, device internal buck is not switching. Pin short during normal condition, no impact. B
CC1 20 VCC Device stops working, CSN/OUT does not output voltage. B
VCC 21 /POL Loss of /POL functionality, the /POL always goes into high, device always appears to have the CC1 pin connected to the CC line. C
/POL 22 /LD_DET Loss of /POL and /LD_LET functionality. C
/LD_DET 23 /FAULT Loss of /FAULT and /LD_LET functionality. C
/FAULT 24 PGND Loss of /FAULT functionality, device always appears to be in the fault condition. C
PGND 25 PGND No effect D
PGND 26 PGND No effect D
PGND 27 SW Device internal buck hiccup, long-term reliability can be impacted. A
SW 28 SW No effect D
SW 29 SW No effect D
SW 30 SW No effect D
SW 31 BOOT Device internal buck HS FET stops working, no output voltage in CSN/OUT. B
Thermal Pad — Any of the numbered pins in the above rows. The thermal pad is connected to the board ground. Treat shorts to the thermal pad as shorts to ground. A
Table 4-5 Pin FMA for Device Pins Short-Circuited to Supply
Pin Name Pin No. Description of Potential Failure Effect(s) Failure Effect Class
VIN 1 No effect D
VIN 2 No effect D
VIN 3 No effect D
EN 4 Device is enabled and cannot be disabled. D
CTRL1 5 Above ABS voltage, device can be damaged. A
CTRL2 6 Above ABS voltage, device can be damaged. A
/THERM_WARN 7 Above ABS voltage, device can be damaged. A
NTC 8 Above ABS voltage, device can be damaged. A
RT/SYNC 9 Above ABS voltage, device can be damaged. A
LS_GD 10 External FET cannot do current limit. C
IMON 11 Above ABS voltage, device can be damaged. A
ILIMT 12 Above ABS voltage, device can be damaged. A
CSN/OUT 13 VBUS OVP protection. FAULT pin asserts. B
CSP 14 VBUS OVP protection. FAULT pin asserts. B
BUS 15 VBUS OVP protection. FAULT pin asserts. B
AGND 16 Former power supply can be pulled down. Device is not powered up. B
DM_IN 17 Above ABS voltage, device can be damaged. A
DP_IN 18 Above ABS voltage, device can be damaged. A
CC2 19 Above ABS voltage, device can be damaged. A
CC1 20 Above ABS voltage, device can be damaged. A
VCC 21 Device broken, VCC pin voltage exceeds the ABS maximum value. A
/POL 22 Above ABS voltage, device can be damaged. A
/LD_DET 23 Above ABS voltage, device can be damaged. A
/FAULT 24 Above ABS voltage, device can be damaged. A
PGND 25 Former power supply can be pulled down. Device is not powered up. B
PGND 26 Former power supply can be pulled down. Device is not powered up. B
PGND 27 Former power supply can be pulled down. Device is not powered up. B
SW 28 Device internal buck stops working. B
SW 29 Device internal buck stops working. B
SW 30 Device internal buck stops working. B
SW 31 Device internal buck stops working. B
BOOT 32 Above ABS voltage, device can be damaged. A
Thermal Pad — Thermal pad is connected to PGND on the PCB board. Former power supply can be pulled down. Device is not powered up. B