1. Reliability and Safety Analysis Team 12: Android Street Car Zongyang Zhu

2. Components Chosen  NXP LPC1768 ARM-M3 32bit microcontroller  TI TPS62160 Step-down Converter  L298 Dual H-Bridge

3. Microcontroller LPC 1768 32bit ARM-M3 uC MIL-Hdbk-217F model: Microprocessors λp = (C1*πT+C2*πE)*πQ*πL C1Die complexity failure fate0.5632 bit uC πTπTTemperature coefficient3.1Tj <= 125C C2Package failure rate0.068128 pin SMT πEπEEnvironment factor4Ground mobile πQπQQuality factor10commercial product πLπLLearning factor1more than 2 years λpλp# failures/10^6 hr20.08 (C1*πT+C2*πE)*πQ*πL MTTFmean time to fail (in years)5.681/λp

4. Power Supply TPS62160 Switching Regulator MIL-Hdbk-217F model: MOS and Digital Devices λp = (C1*πT+C2*πE)*πQ*πL C1Die complexity failure fate0.04<= 1000 transistors πTπTTemperature coefficient3.1Tj <= 125C C2Package failure rate0.00348 pin SMT πEπEEnvironment factor4Ground mobile πQπQQuality factor10commercial product πLπLLearning factor1more than 2 years λpλp# failures/10^6 hr1.376(C1*πT+C2*πE)*πQ*πL MTTFmean time to fail (in years)82.851/λp

5. Motor Control L298 Dual H-Bridge MIL-Hdbk-217F model: Microprocessors λp = (C1*πT+C2*πE)*πQ*πL C1Die complexity failure fate0.01<= 100 transistors πTπTTemperature coefficient58Tj <= 150C C2Package failure rate0.005615 pin SMT πEπEEnvironment factor4Ground mobile πQπQQuality factor10commercial product πLπLLearning factor1more than 2 years λpλp# failures/10^6 hr6.024(C1*πT+C2*πE)*πQ*πL MTTFmean time to fail (in years)18.92 1/λp

6. Criticality Levels  High Criticality  Possibility to cause injuries  Acceptable mean failure rate 10 -9  Medium Criticality  Overheating of components  Acceptable mean failure rate 10 -7  Lower Criticality  Failure is easily recoverable  Acceptable mean failure rate 10 -6

7. Schematic – Power Supply

8. Schematic - Microcontroller

9. FMECA - Microcontroller Failure No. Failure modePossible CauseFailure Effects Method of Detection Criticality A1no clock in uCdamaged 12 crystal no output from uC, cannot enter ISP mode ObservationLow A2 currupt data output at SPI/UART cold joint at headerssystem not responsiveObservationLow A3VCC = 0V Bypass capacitor breakdown Overheating of power supply ObservationMedium

10. FMECA - Others Failure No. Failure modePossible CauseFailure Effects Method of Detection Criticality B1 power supply Vout=0 R1 is open no power for the whole system ObservationLow B2 power supply overheating C2, C3, C4 breakdown overheating, no power for system ObservationMedium C1 hbridge no output Hbridge failure system can respond but no motion ObservationLow

11. Questions?