SFFS163 May   2021 DRV8871-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)

Failure Mode Distribution (FMD)

The failure mode distribution estimation for DRV8871-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 due to misuse or overstress.

Table 3-1 Die Failure Modes and Distribution
Die Failure ModesFailure Mode Distribution (%)
OUTx is stuck low when commanded OFF16%
OUTx is stuck OFF when commanded LOW10%
OUTx ON resistance too high when commanded LOW14%
OUTx is stuck HIGH when commanded OFF16%
OUTx is stuck OFF when commanded HIGH10%
OUTx ON resistance too high when commanded HIGH19%
Dead-time is too short1%
ITRIP current regulation incorrect4%
Incorrect fault response10%