SFFS114 March   2021 DRV8899-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 DRV8899-Q1. The failure modes covered in this document include the typical pin-by-pin failure scenarios:

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 package pin diagram. For a detailed description of the device pins please refer to the 'Pin Configuration and Functions' section in the datasheet.

GUID-3134A119-D60E-4DC6-864A-102B7F18C369-low.gifFigure 4-1 Pin Diagram

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

  • The device is used with external components consistent with the values described in the external component table of the datasheet.

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

VM

1

Device will not power up

B

PGND

2

Intended Operation

D

AOUT1

3

Device will signal OCP fault

B

AOUT2

4

Device will signal OCP fault

B

BOUT2

5

Device will signal OCP fault

B

BOUT1

6

Device will signal OCP fault

B

PGND

7

Intended Operation

D

VM

8

Device will signal OCP fault

B

GND

9

Intended Operation

D

DVDD

10

Device external digital power supply stuck low. Device non-operational.

B

nFAULT

11

Device will always be signaling fault

B

VREF

12

Current regulation will be lost

B

nSCS

13

SPI read write functions will be non-functional

B

VSDO

14

SPI read function will be non-functional

B

SDO

15

SPI read function will be non-functional

B

SDI

16

SPI read write functions will be non-functional

B

SCLK

17

SPI read write functions will be non-functional

B

STEP

18

STEP input capability will be lost

B

DIR

19

Direction change capability will be lost

B

DRVOFF

20

Driver control will be lost

B

nSLEEP

21

Device will be in sleep state with OUTx Hi-Z

B

CPL

22

Device charge pump non-operational. Device CPUV fault.

A

CPH

23

Device charge pump non-operational. Device CPUV fault.

A

VCP

24

Device charge pump non-operational. Device CPUV fault.

A

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

VM

1

Device will not power up

B

PGND

2

Device will not power up

B

AOUT1

3

Device will not be able to drive the load properly

B

AOUT2

4

Device will not be able to drive the load properly

B

BOUT2

5

Device will not be able to drive the load properly

B

BOUT1

6

Device will not be able to drive the load properly

B

PGND

7

Device will not power up

B

VM

8

Device will not power up

B

GND

9

Device will not power up

B

DVDD

10

Device external digital power supply missing. Device non-operational.

B

nFAULT

11

Fault signaling will be lost

B

VREF

12

Current regulation will be lost

B

nSCS

13

SPI read write functions will be non-functional

B

VSDO

14

SPI read function will be non-functional

B

SDO

15

SPI read function will be non-functional

B

SDI

16

SPI read write functions will be non-functional

B

SCLK

17

SPI read write functions will be non-functional

B

STEP

18

Driver control will be lost

B

DIR

19

Driver control will be lost

B

DRVOFF

20

Driver control will be lost

B

nSLEEP

21

Device will be in sleep state

B

CPL

22

Device charge pump non-operational. Device CPUV fault.

B

CPH

23

Device charge pump non-operational. Device CPUV fault.

B

VCP

24

Device charge pump non-operational. Device CPUV fault.

B

Table 4-4 QFN Package - Pin FMA for Device Pins Shorted to Adjacent Pin
Pin NamePin No.Shorted to Pin No.Description of Potential Failure Effect(s)Failure Effect Class

VM

1

2

Device will not power up

B

PGND

2

3

Device will signal OCP fault

B

AOUT1

3

4

Device will signal OCP fault

B

AOUT2

4

5

Device will signal OCP fault

B

BOUT2

5

6

Device will signal OCP fault

B

BOUT1

6

7

Device will signal OCP fault

B

PGND

7

8

Device will not power up

B

VM

8

9

Device will not power up

B

GND

9

10

Device external digital power supply stuck low. Device non-operational.

B

DVDD

10

11

Device will reset whenever nFAULT is asserted low

B

nFAULT

11

12

Current regulation and fault signalling will be lost

B

VREF

12

13

Current regulation and SPI read write functions will be non-functional

B

nSCS

13

14

SPI read write functions will be non-functional

B

VSDO

14

15

SPI read write functions will be non-functional

B

SDO

15

16

SPI read write functions will be non-functional

B

SDI

16

17

SPI read write functions will be non-functional

B

SCLK

17

18

SPI read write functions and GPIO step input will be non-functional

B

STEP

18

19

STEP input and direction change capabilities will be lost

B

DIR

19

20

Direction change and OUTx control will be lost

B

DRVOFF

20

21

Driver control will be lost

B

nSLEEP

21

22

Device charge pump non-operational. Device CPUV fault.

A

CPL

22

23

Device charge pump non-operational. Device CPUV fault.

A

CPH

23

24

Device charge pump non-operational. Device CPUV fault.

A

VCP

24

1

Device charge pump non-operational. Device CPUV fault.

B

Table 4-5 QFN Package - Pin FMA for Device Pins Shorted to VM (High Voltage Supply)
Pin NamePin No.Description of Potential Failure Effect(s)Failure Effect Class

VM

1

Intended Operation

D

PGND

2

Device will not power up

B

AOUT1

3

Device will signal OCP fault

B

'AOUT2

4

Device will signal OCP fault

B

BOUT2

5

Device will signal OCP fault

B

BOUT1

6

Device will signal OCP fault

B

PGND

7

Device will not power up

B

VM

8

Intended Operation

D

GND

9

Device will not power up

B

DVDD

10

Low voltage pin max voltage violated.

A

nFAULT

11

Low voltage pin max voltage violated.

A

VREF

12

Low voltage pin max voltage violated.

A

nSCS

13

Low voltage pin max voltage violated.

A

VSDO

14

Low voltage pin max voltage violated.

A

SDO

15

Low voltage pin max voltage violated.

A

SDI

16

Low voltage pin max voltage violated.

A

SCLK

17

Low voltage pin max voltage violated.

A

STEP

18

Low voltage pin max voltage violated.

A

DIR

19

Low voltage pin max voltage violated.

A

DRVOFF

20

Low voltage pin max voltage violated.

A

nSLEEP

21

Driver control will be lost

B

CPL

22

Device charge pump non-operational. Device CPUV fault.

A

CPH

23

Device charge pump non-operational. Device CPUV fault.

A

VCP

24

Device charge pump non-operational. Device CPUV fault.

B