SFFS153 September   2021 TPS62441-Q1 , TPS62442-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 TPS6244x-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 TPS6244x-Q1 pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the TPS6244x-Q1 data sheet.

GUID-622718CC-74C0-4EA4-B98E-3B4A019748F7-low.gifFigure 4-1 Pin Diagram

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

  • Assumption the device is running in the typical application, please refer to the 'Simplified Schematics' on the 1st page in the TPS6244x-Q1 data sheet.

Table 4-2 Pin FMA for Device Pins Short-Circuited to Ground
Pin NamePin No.Description of Potential Failure Effect(s)Failure Effect Class

FB2

1

Converter 2 output voltage regulated to VIN (100% mode)

B

GND

2

No effect, normal operation

D

FB1

3

Converter 1 output voltage regulated to VIN (100% mode)

B

PG1

4

No operation, no power good indication

B

MODE/SYNC

5

Intended functionality

D

SW1

6

Potential device damage

A

VIN1

7

Converter 1 does not power up, no output voltage on converter 1

B

EN1

8

Converter 1 is disabled, no output voltage on converter 1

B

GND

9

No effect, normal operation

D

EN2

10

Converter 2 is disabled, no output voltage on converter 2

B

VIN2

11

Converter 2 does not power up, no output voltage on converter 2

B

SW2

12

Potential device damage

A

PG2

13

No operation, no power good indication

B

COMP/FSET

14

Intended functionality, device operates in fix frequency

D

Table 4-3 Pin FMA for Device Pins Open-Circuited
Pin NamePin No.Description of Potential Failure Effect(s)Failure Effect Class

FB2

1

Undetermined output voltage behavior of converter 2; open loop operation

B

GND

2

Device does not power up, no output volatge

B

FB1

3

Undetermined output voltage behavior of converter 1; open loop operation

B

PG1

4

Intended functionality

B

MODE/SYNC

5

Undetermined device operation

B

SW1

6

Output volatge 1 not functional, open loop operation.

B

VIN1

7

Converter 1 does not power up

B

EN1

8

Undetermined device operation; converter 1 might power up or not

B

GND

9

Device does not power up, no output volatge

B

EN2

10

Undetermined device operation; converter 2 might power up or not

B

VIN2

11

Converter 2 does not power up

B

SW2

12

Converter 2 not functional, open loop operation.

B

PG2

13

Intended functionality

B

COMP/FSET

14

Normal operation

D

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

FB1

3

PG1

Converter 2 does not regulate

B

PG1

4

MODE/SYNC

No device damage, but performance degradation

B

MODE/SYNC

5

SW1

Potential internal device damage

A

SW2

12

PG2

Potential internal device damage

A

PG2

13

COMP/FSET

Potential internal device damage

A

COMP/FSET

14

FB2

Converter 2 does not regulate

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

FB2

1

Potential device damage

A

GND

2

Device does not power up, no output voltage

B

FB1

3

Potential device damage

A

PG1

4

Potential device damage

A

MODE/SYNC

5

Intended functionality; FPWM mode

D

SW1

6

Potential device damge

A

VIN1

7

Normal operation

D

EN1

8

Intended functionality; Converter 1 enable

D

GND

9

Device does not power up, no output voltage

B

EN2

10

Intended functionality; Converter 2 enable

D

VIN2

11

Normal operation

D

SW2

12

Potential device damge

A

PG2

13

Potential device damage

A

COMP/FSET

14

Intended functionality; device operates in fix frequency

D