UCC28C4x-Q1 Functional Safety FIT Rate, FMD and Pin FMA

1 Overview

This document contains information for UCC28C4x-Q1(UCC28C40-Q1, UCC28C41-Q1, UCC28C42-Q1, UCC28C43-Q1, UCC28C44-Q1, and UCC28C45-Q1) (SOIC (8) 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
Pin failure mode analysis (Pin FMA)

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

Note:

Toggle flip-flop used only in UCC28C41-Q1, UCC28C44-Q1, and UCC28C45-Q1

Figure 1-1 Functional Block Diagram

UCC28C4x-Q1 was developed using a quality-managed development process, but was not developed in accordance with the IEC 61508 or ISO 26262 standards.

Table 1-1 Device Comparison Table

UVLO			MAXIMUM DUTY CYCLE	TEMPERATURE (T_A)
TURN ON AT 14.5 V TURN OFF AT 9 V SUITABLE FOR OFF-LINE APPLICATIONS	TURN ON AT 8.4 V TURN OFF AT 7.6 V SUITABLE FOR DC/DC APPLICATIONS	TURN ON AT 7 V TURN OFF AT 6.6 V SUITABLE FOR BATTERY APPLICATIONS	MAXIMUM DUTY CYCLE	TEMPERATURE (T_A)
UCC28C42QDRQ1	UCC28C43QDRQ1	UCC28C40QDRQ1	100%	–40°C to 125°C
UCC28C44QDRQ1	UCC28C45QDRQ1	UCC28C41QDRQ1	50%	–40°C to 125°C

2 Functional Safety Failure In Time (FIT) Rates

2.1 SOIC (8) Package

This section provides Functional Safety Failure In Time (FIT) rates for SOIC (8) package of UCC28C4x-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

Table 2-1 Component Failure Rates per IEC TR 62380 / ISO 26262 Part 11

FIT IEC TR 62380 / ISO 26262	FIT (Failures Per 10⁹ Hours)
Total Component FIT Rate (71.6 mW, 150 mW, 300 mW)	10, 11, 15
Die FIT Rate (71.6 mW, 150 mW, 300 mW)	3, 4, 7
Package FIT Rate (71.6 mW, 150 mW, 300 mW)	7, 7, 8

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: 71.6 mW, 150mW, 300mW
Climate type: World-wide Table 8
Package factor (lambda 3): Table 17b
Substrate Material: FR4
EOS FIT rate assumed: 0 FIT

Table 2-2 Component Failure Rates per Siemens Norm SN 29500-2

Table	Category	Reference FIT Rate	Reference Virtual T_J
5	CMOS, BICMOS Digital, analog / mixed	25 FIT	55°C

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.

3 Failure Mode Distribution (FMD)

The failure mode distribution estimation for UCC28C4x-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 Modes	Failure Mode Distribution (%)
OUT stuck low	34
OUT pulse width not as expected	19
OUT stuck high	14
System is unstable	11
No effect	22