SFFS044 January   2021 TPS2HB16-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)

Pin Failure Mode Analysis (Pin FMA)

This section provides a Failure Mode Analysis (FMA) for the pins of the TPS2HB16-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
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 TPS2HB16-Q1 pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the TPS2HB16-Q1 data sheet.

GUID-714552FE-3FA6-4E96-8AE7-300DC1576418-low.gifFigure 4-1 Pin Diagram Version A, B
GUID-9B8610CF-DC21-467C-8DCD-AB2476CC4AEC-low.svgFigure 4-2 Pin Diagram Version F

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

  • Follow data sheet recommendation for operating conditions, external component selection and PCB layout
Table 4-2 Pin FMA for Device Pins Short-Circuited to Ground
Pin NamePin No.Description of Potential Failure Effect(s)Failure Effect Class
GND1Resistor/diode network will be bypassed if present.B
SNS2SNS current diagnostic not available.B
LATCH3Normal operation. With device in auto-retry mode.B
EN14Normal operation with channel 1 output off (FET turned off).B
ILIM15Current Limit for channel 1 defaults to internal limit. C
FLT15Version F only. Channel 1 open drain fault diagnostics cannot be reported.B
VOUT16,7,8Short to GND protection kicks in to protect the device. B
VOUT29,10,11Short to GND protection kicks in to protect the device. B
ILIM212Current Limit for channel 2 defaults to internal limit. C
FLT212Version F only. Channel 2 open drain fault diagnostics cannot be reported.B
EN213Normal operation with channel 2 output off (FET turned off). B
SEL114Normal operation with diagnostics corresponding to SEL1=LOW. B
SEL215Normal operation with diagnostics corresponding to SEL2=LOW. B
DIAG_EN16Normal operation with diagnostics function disabled. B
Table 4-3 Pin FMA for Device Pins Open-Circuited
Pin NamePin No.Description of Potential Failure Effect(s)Failure Effect Class
GND1The output is off with the FET turned off. B
SNS2SNS current diagnostic not available.B
LATCH3Normal operation with device in auto-retry mode. Internal pull=down resistor will pull pin to GND. B
EN14Normal operation with channel 1 output off (FET turned off). Internal pull-down resistor will pull pin to GND. B
ILIM15Current Limit for channel 1 defaults to internal limit. C
FLT15Version F only. Channel 1 open drain fault diagnostics cannot be reported.B
VOUT16,7,8Channel 1 Output off. Open load detection will be triggered in off-state while in diagnostics state. B
VOUT29,10,11Channel 2 Output off. Open load detection will be triggered in off-state while in diagnostics state.
ILIM212Current Limit for channel 2 defaults to internal limit.C
FLT212Version F only. Channel 2 open drain fault diagnostics cannot be reported.B
EN213Normal operation with channel 2 output off (FET turned off). Internal pull-down resistor will pull pin to GND. B
SEL114Normal operation with diagnostics corresponding to SEL1=LOW. Internal pull-down resistor will pull pin to GND. B
SEL215Normal operation with diagnostics corresponding to SEL2=LOW. Internal pull-down resistor will pull pin to GND.B
DIAG_EN16Normal operation with diagnostics function disabled. Internal pull-down resistor will pull pin to GND. B
Table 4-4 Pin FMA for Device Pins Short-Circuited to Adjacent Pin
Pin NamePin No.Shorted toDescription of Potential Failure Effect(s)Failure Effect Class
GND12 (SNS)SNS current diagnostic not available. B
SNS23 (LATCH)Undefined device behavior and depends on pin voltage. Sense output may not be correct. Latch function may be enabled if pin voltage > VIH; latch function may be disabled if pin voltage < VIL.B
LATCH34 (EN)Device behavior depends on pin voltage. Latch function may be enabled if pin voltage > VIH; Latch function may be disabled if pin voltage < VIL.B
EN145 (ILIM1)Undefined device behavior. Channel may be enabled if pin voltage > VIH; channel may be disabled if pin voltage < VIL. Channel 1 current limit threshold will not be correct. B
EN145 (FLT1)Version F only. Undefined device behavior. Channel may be enabled if pin voltage > VIH; channel may be disabled if pin voltage < VIL. Channel 1 open drain fault diagnostics cannot be reported.B
ILIM156 (VOUT1)Undefined device behavior. Current limit threshold (ch1) will not be correct or short circuit/overload protection may not function. VOUT of Ch1 behavior may not be correct.B
FLT156 (VOUT1)Version F only. Channel 1 open drain fault diagnostics cannot be reported. VOUT of Ch1 behavior may not be correct.B
VOUT16,7,85 (ILIM1)Undefined device behavior. Current limit threshold (ch1) will not be correct or short circuit/overload protection may not function. VOUT of Ch1 behavior may not be correct.A
VOUT16,7,85 (FLT1)Version F only. Channel 1 open drain fault diagnostics cannot be reported. VOUT of Ch1 behavior may not be correct.B
VOUT29,10,11

12 (ILIM2)

Undefined device behavior. Current limit threshold (ch2) will not be correct or short circuit/overload protection may not function. VOUT of Ch2 behavior may not be correct.

A

VOUT29,10,1112 (FLT2)Version F only. Undefined device behavior. Channel 1 open drain fault diagnostics cannot be reported. VOUT of Ch2 behavior may not be correct. B
ILIM21213 (EN2)Undefined device behavior. Channel may be enabled if pin voltage > VIH; channel may be disabled if pin voltage < VIL. Channel 2 current limit threshold will not be correct. B
FLT21213 (EN2)Version F only. Undefined device behavior. Channel may be enabled if pin voltage > VIH; channel may be disabled if pin voltage < VIL. Channel 1 open drain fault diagnostics cannot be reported.B
EN213

14 (SEL1)

Undefined device behavior. Ch2 may be enabled if pin voltage > VIH; Ch2 may be disabled if pin voltage < VIL.

B

SEL11415 (SEL2)Device behavior depends on adjacent pin voltage affecting diagnostic output. B
SEL21516 (DIAG_EN)Device behavior depends on adjacent pin voltage affecting diagnostic output. Diagnostic function may be enabled if pin voltage > VIH; Diagnostic function may be disabled if pin voltage < VIL. B
DIAG_EN1615 (SEL2)Device behavior depends on adjacent pin voltage affecting diagnostic output. Diagnostic function may be enabled if pin voltage > VIH; Diagnostic function may be disabled if pin voltage < VIL. B
Table 4-5 Pin FMA for Device Pins Short-Circuited to supply
Pin NamePin No.Description of Potential Failure Effect(s)Failure Effect Class
GND1Supply power will be bypassed and device will not turn on.B
SNS2Undefined device behavior; may cause device damage due to voltage breakdown on ESD circuit.A
LATCH3If pin voltage exceeds the pin data sheet range, it may cause device damage due to voltage breakdown on ESD circuit. Device behavior depends on supply voltage.A
EN14Undefined device behavior; if pin voltage exceeds the pin data sheet range, it may cause device damage due to voltage breakdown on ESD circuit.A
ILIM15Normal operation but with ch1 higher current limit programmed with internal reference. No device damage.C
FLT15Version F only. Channel 1 open drain fault diagnostics cannot be reportedB
VOUT6,7,8,9,10,11Output 1 stuck on to supply. Open load detection will be triggered in off-state in diagnostics state. C

VOUT2

9,10,11

Output 2 stuck on to supply. Open load detection will be triggered in off-state in diagnostics state.

C

ILIM212Normal operation but with ch2 higher current limit programmed with internal reference. C
FLT212Version F only. Channel 2 open drain fault diagnostics cannot be reported.B

EN2

13

Undefined device behavior; if pin voltage exceeds the pin data sheet range, it may cause device damage due to voltage breakdown on ESD circuit.

A

SEL114Undefined device behavior; if pin voltage exceeds the pin data sheet range, it may cause device damage due to voltage breakdown on ESD circuit.A

SEL2

15

Undefined device behavior; if pin voltage exceeds the pin data sheet range, it may cause device damage due to voltage breakdown on ESD circuit.

A

DIAG_EN16Undefined device behavior; if pin voltage exceeds the pin data sheet range, it may cause device damage due to voltage breakdown on ESD circuit.A