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This document contains information for the DRV8262-Q1 to aid in a functional safety system design. Information provided are:
Figure 1-1 shows the device functional block diagram for reference.
The DRV8262-Q1 was developed using a quality-managed development process, but was not developed in accordance with the IEC 61508 or ISO 26262 standards.
This section provides functional safety failure in time (FIT) rates for the DRV8262-Q1 based on two different industry-wide used reliability standards:
FIT IEC TR 62380 / ISO 26262 | FIT (Failures Per 109 Hours) |
---|---|
Total component FIT rate | 44 |
Die FIT rate | 5 |
Package FIT rate | 39 |
The failure rate and mission profile information in Table 2-1 comes from the reliability data handbook IEC TR 62380 / ISO 26262 part 11:
Table | Category | Reference FIT Rate | Reference Virtual TJ |
---|---|---|---|
5 | CMOS/BICMOS ASICs Analog & Mixed =<50V supply | 60 FIT | 70°C |
The reference FIT rate and reference virtual TJ (junction temperature) in Table 2-2 come from the Siemens Norm SN 29500-2 tables 1 through 5. Failure rates under operating conditions are calculated from the reference failure rate and virtual junction temperature using conversion information in SN 29500-2 section 4.
The failure mode distribution estimation for the DRV8262-Q1 in Table 3-1 comes from the combination of common failure modes listed in standards such as IEC 61508 and ISO 26262, the ratio of sub-circuit function size and complexity, and from best engineering judgment.
The failure modes listed in this section reflect random failure events and do not include failures resulting from misuse or overstress.
Die Failure Modes | Failure Mode Distribution |
---|---|
xOUTx is stuck LOW when commanded OFF | 9 % |
xOUTx is stuck OFF when commanded LOW | 12 % |
xOUTx ON resistance too high when commanded LOW | 9 % |
Low side slew rate too fast or too slow | 3 % |
xOUTx is stuck HIGH when commanded OFF | 9 % |
xOUTx is stuck OFF when commanded HIGH | 12 % |
xOUTx ON resistance too high when commanded HIGH | 9 % |
High side slew rate too fast or too slow | 3 % |
Dead time is too short | 3 % |
Incorrect communication or fault indication | 12 % |
Current regulation incorrect | 19 % |
This section provides a failure mode analysis (FMA) for the pins of the DRV8262-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.
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 shows the DRV8262-Q1 pin diagram. For a detailed description of the device pins, see the Pin Configuration and Functions section in the DRV8262-Q1 data sheet.
Following are the assumptions of use and the device configuration assumed for the pin FMA in this section:
Pin Name | Pin No. | Description of Potential Failure Effect(s) | Failure Effect Class |
---|---|---|---|
VCP | 1 | Device charge pump non-operational | A |
VM | 2, 11, 12, 21 | Device will not power up | B |
PGND12 / PGND | 3, 10 | Intended Operation | D |
OUT1 | 4, 5, 6 | Device will signal OCP fault | B |
OUT2 | 7, 8, 9 | Device will signal OCP fault | B |
PGND34 / PGND | 13, 20 | Intended Operation | D |
OUT4 / OUT2 | 14, 15, 16 | Device will signal OCP fault | B |
OUT3 / OUT1 | 17, 18, 19 | Device will signal OCP fault | B |
GND | 22, 23 | Intended Operation | D |
DVDD | 24 | Device digital supply stuck low. Device non-operational. Drivers disabled. | B |
VCC | 25 | Device digital supply stuck low. Device non-operational. Drivers disabled. | B |
nFAULT | 26 | Device will always be signaling fault | B |
OCPM | 27 | Device only works with latch-off type recovery for OCP and OTSD | B |
MODE1 | 28 | Device only works in Dual H-bridge mode | B |
MODE2 | 29 | Device only works in PH/EN mode | B |
IPROPI2 / IPROPI | 30 | Current sense output will not be available | B |
IPROPI1 / IPROPI | 31 | Current sense output will not be available | B |
RSVD | 32, 36 | No impact to functioality | D |
VREF2 / VREF | 33 | Current regulation will be lost | B |
VREF1 / VREF | 34 | Current regulation will be lost | B |
TOFF | 35 | OFF time will be permanently set at 7 us | B |
DECAY | 37 | Device will work only with slow decay | B |
IN4 | 38 | OUT4 will be stuck low | B |
IN3 | 39 | OUT3 will be stuck low | B |
IN2 | 40 | OUT2 will be stuck low | B |
IN1 | 41 | OUT1 will be stuck low | B |
nSLEEP | 42 | Device will be in sleep state with OUTx Hi-Z | B |
CPL | 43 | Device charge pump non-operational | B |
CPH | 44 | Device charge pump non-operational | A |
Pin Name | Pin No. | Description of Potential Failure Effect(s) | Failure Effect Class |
---|---|---|---|
VCP | 1 | Device charge pump non-operational | B |
VM | 2, 11, 12, 21 | Device will not power up | B |
PGND12 / PGND | 3, 10 | Device will not power up | B |
OUT1 | 4, 5, 6 | Device will not be able to drive the load properly | B |
OUT2 | 7, 8, 9 | Device will not be able to drive the load properly | B |
PGND34 / PGND | 13, 20 | Device will not power up | B |
OUT4 / OUT2 | 14, 15, 16 | Device will not be able to drive the load properly | B |
OUT3 / OUT1 | 17, 18, 19 | Device will not be able to drive the load properly | B |
GND | 22, 23 | Device will not power up | B |
DVDD | 24 | Device digital supply missing. Device non-operational. | B |
VCC | 25 | Device digital supply missing. Device non-operational. | B |
nFAULT | 26 | Fault signaling will be lost | B |
OCPM | 27 | Device only works with latch-off type recovery for OCP and OTSD | B |
MODE1 | 28 | Device only works in dual H-bridge mode | B |
MODE2 | 29 | Device only works in PWM mode | B |
IPROPI2 / IPROPI | 30 | Current sense output will not be available | B |
IPROPI1 / IPROPI | 31 | Current sense output will not be available | B |
RSVD | 32, 36 | No impact to functionality | D |
VREF2 / VREF | 33 | Current regulation will be lost | B |
VREF1 / VREF | 34 | Current regulation will be lost | B |
TOFF | 35 | OFF time will be permanently set at 24us | B |
DECAY | 37 | Device will work only with mixed decay | B |
IN4 | 38 | PWM functionality will not be available for OUT4 | B |
IN3 | 39 | PWM functionality will not be available for OUT3 | B |
IN2 | 40 | PWM functionality will not be available for OUT2 | B |
IN1 | 41 | PWM functionality will not be available for OUT1 | B |
nSLEEP | 42 | Device will be in sleep state with OUTx Hi-Z | B |
CP | 43 | Device charge pump non-operational | B |
CPH | 44 | Device charge pump non-operational | B |
Pin Name | Pin No. | Shorted to Pin No. | Description of Potential Failure Effect(s) | Failure Effect Class |
---|---|---|---|---|
VCP | 1 | 2 | Device charge pump non-operational | B |
VM | 2 | 3 | Device will not power up | B |
PGND12 | 3 | 4 | Device will signal OCP fault | B |
OUT1 | 4 | 5 | Intended Operation | D |
OUT1 | 5 | 6 | Intended Operation | D |
OUT1 | 6 | 7 | Device will signal OCP fault | B |
OUT2 | 7 | 8 | Intended Operation | D |
OUT2 | 8 | 9 | Intended Operation | D |
OUT2 | 9 | 10 | Device will signal OCP fault | B |
PGND12 | 10 | 11 | Device will not power up | B |
VM | 11 | 12 | Intended Operation | D |
VM | 12 | 13 | Device will not power up | B |
PGND34 | 13 | 14 | Device will signal OCP fault | B |
OUT4 | 14 | 15 | Intended Operation | D |
OUT4 | 15 | 16 | Intended Operation | D |
OUT4 | 16 | 17 | Device will signal OCP fault | B |
OUT3 | 17 | 18 | Intended Operation | D |
OUT3 | 18 | 19 | Intended Operation | D |
OUT3 | 19 | 20 | Device will signal OCP fault | B |
PGND34 | 20 | 21 | Device will not power up | B |
VM | 21 | 22 | Device will not power up | B |
GND | 22 | 23 | Intended Operation | D |
GND | 23 | 24 | Digital supply missing. Device non-operational. | B |
DVDD | 24 | 25 | Digital supply missing. Device non-operational. | B |
VCC | 25 | 26 | Device will reset whenever nFAULT is asserted low | B |
nFAULT | 26 | 27 | OCP/OTSD recovery setting and fault signal will be lost | B |
OCPM | 27 | 28 | OCP/OTSD recovery and MODE setting will be lost | B |
MODE1 | 28 | 29 | MODE setting will be lost | B |
MODE2 | 29 | 30 | MODE setting and current sense output function will be lost | B |
IPROPI2 | 30 | 31 | Current sense output functionality will be lost | B |
IPROPI1 | 31 | 32 | No impact to functionality | D |
RSVD | 32 | 33 | No impact to functionality | D |
VREF2 | 33 | 34 | Independent current regulation will be non-functional | B |
VREF1 | 34 | 35 | Current regulation and off time setting will be non-functional | B |
TOFF | 35 | 36 | No impact to functionality | D |
RSVD | 36 | 37 | No impact to functionality | D |
DECAY | 37 | 38 | Decay mode setting and input PWM function will be lost | B |
IN4 | 38 | 39 | Input PWM functionality will be lost | B |
IN3 | 39 | 40 | Input PWM functionality will be lost | B |
IN2 | 40 | 41 | Input PWM functionality will be lost | B |
IN1 | 41 | 42 | Input PWM and Sleep mode function will be lost | B |
nSLEEP | 42 | 43 | Device charge pump non-operational | A |
CPL | 43 | 44 | Device charge pump non-operational | B |
CPH | 44 | 1 | Device charge pump non-operational | B |
Pin Name | Pin No. | Description of Potential Failure Effect(s) | Failure Effect Class |
---|---|---|---|
VCP | 1 | Device charge pump non-operational | B |
VM | 2, 11, 12, 21 | Intended Operation | D |
PGND12 / PGND | 3, 10 | Device will not power up | B |
OUT1 | 4, 5, 6 | Device will signal OCP fault | B |
OUT2 | 7, 8, 9 | Device will signal OCP fault | B |
PGND34 / PGND | 13, 20 | Device will not power up | B |
OUT4 / OUT2 | 14, 15, 16 | Device will signal OCP fault | B |
OUT3 / OUT1 | 17, 18, 19 | Device will signal OCP fault | B |
GND | 22, 23 | Device will not power up | B |
DVDD | 24 | Low voltage pin maximum voltage violated | A |
VCC | 25 | Low voltage pin maximum voltage violated | A |
nFAULT | 26 | Low voltage pin maximum voltage violated | A |
OCPM | 27 | Low voltage pin maximum voltage violated | A |
MODE1 | 28 | Low voltage pin maximum voltage violated | A |
MODE2 | 29 | Low voltage pin maximum voltage violated | A |
IPROPI2 / IPROPI | 30 | Low voltage pin maximum voltage violated | A |
IPROPI1 / IPROPI | 31 | Low voltage pin maximum voltage violated | A |
RSVD | 32, 36 | Low voltage pin maximum voltage violated | A |
VREF2 / VREF | 33 | Low voltage pin maximum voltage violated | A |
VREF1 / VREF | 34 | Low voltage pin maximum voltage violated | A |
TOFF | 35 | Low voltage pin maximum voltage violated | A |
DECAY | 37 | Low voltage pin maximum voltage violated | A |
IN4 | 38 | Low voltage pin maximum voltage violated | A |
IN3 | 39 | Low voltage pin maximum voltage violated | A |
IN2 | 40 | Low voltage pin maximum voltage violated | A |
IN1 | 41 | Low voltage pin maximum voltage violated | A |
nSLEEP | 42 | Driver control will be lost | B |
CPL | 43 | Device charge pump non-operational | A |
CPH | 44 | Device charge pump non-operational | B |