This document contains information for TPS2556-Q1 and TPS2557-Q1 (DRB package) to aid in a functional safety system design. Information provided are:

• Functional Safety Failure In Time (FIT) rates of the semiconductor component estimated by the application of industry reliability standards
• Component failure modes and their distribution (FMD) based on the primary function of the device

Figure 1-1 shows the device functional block diagram for reference.

Figure 1-1 Functional Block Diagram

TPS2556-Q1 and TPS2557-Q1 were developed using a quality-managed development process, but were not developed in accordance with the IEC 61508 or ISO 26262 standards.

This section provides Functional Safety Failure In Time (FIT) rates for TPS2556-Q1 and TPS2557-Q1 based on two different industry-wide used reliability standards:

• Table 2-1 provides FIT rates based on IEC TR 62380 / ISO 26262 part 11
• Table 2-2 provides FIT rates based on the Siemens Norm SN 29500-2

The failure rate and mission profile information in Table 2-1 comes from the Reliability data handbook IEC TR 62380 / ISO 26262 part 11:

• Mission Profile: Motor Control from Table 11
• Power dissipation: 750 mW
• Climate type: World-wide Table 8
• Package factor (lambda 3): Table 17b
• Substrate Material: FR4
• EOS FIT rate assumed: 0 FIT

The Reference FIT Rate and Reference Virtual T_J (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.