Reliability and Safety Analysis Ryan Pawling Team 3

Definition of Criticality Levels Low Criticality Does not present harm to the user Is repairable and not destructive to the rest of the board Failure rate of 10-6 or less is acceptable Medium Criticality Could damage the entire board, render it unusable Failure rate of 10-7 or less is acceptable High Criticality Poses potential harm to the user Failure rate of 10-9 or less is acceptable Our board doesn't have failure modes with high criticality

Safety Considerations Malfunction in software or LED driver could produce a strobing effect; trigger epileptic seizures Game has many small pieces that could be swallowed Not recommended for small children

Components Chosen for Analysis TI LM2675 Voltage Regulator Atmel AT32UC3B Microcontroller Omron W2RV004RM RGB LED Driver AS1116 7 Segment Driver

Atmel AT32UC3B Microcontroller Parameter name Description Value Comments C1 Die complexity 0.56 32-bit microcontroller πT Temperature coeff. 0.98 operating at 85 C C2 Packaging Failure coeff. 0.032 64-pin SMD πE Environmental Factor 2.0 Ground, fixed πQ Quality Factor 10.0 Commercial part πL Learning Factor 1.0 > 2 years ℷP Reliability 6.128 Exceeds desired failure rate MTTF Entire Design 6.128 x 10-6 1 micro on board

LM2675M Voltage Regulator Parameter name Description Value Comments C1 Die complexity 0.0010 1001-3000 gates πT Temperature coeff. 16 operating at < 100C C2 Packaging Failure coeff. 0.0072 16-pin SMD πE Environmental Factor 2.0 Ground, fixed πQ Quality Factor 10.0 Commercial part πL Learning Factor 1.0 > 2 years ℷP Reliability 0.304 Exceeds desired failure rate MTTF Entire Design 3.04x 10-7 1 Buck on board

FEMCA Subset Failure Mode Possible Causes Failure Effects Method of Detection Criticality Reset is triggered on the micro Pull-up resistor for reset switch is shorted, reset switch is stuck closed Game board will restart Observation Low 7 Segment driver registers do not latch new data SPI bus too noisy, driver failure, microcontroller load signal failure/timing error Rarity cannot be displayed on the board or changed RGB driver channel is not modulating Internal RGB PWM failure, input/out pins on driver/micro are faulty, software LED on the affected channel will not be driven Unstable 3.3 Voltage on the board Too much current draw from 7 segment displays, 7 segment driver or buck switcher is too noisy, bulk capacitor failure Seven segment displays flicker, board freezes and becomes unresponsive

Questions

Omron W2V004RM RGB LED Driver Parameter name Description Value Comments C1 Die complexity 0.0020 3001-10000 gates πT Temperature coeff. 0.98 operating at 85 C C2 Packaging Failure coeff. 0.013 28-pin SMD πE Environmental Factor 2.0 Ground, fixed πQ Quality Factor 10.0 Commercial part πL Learning Factor 1.0 > 2 years ℷP Reliability 0.280 Exceeds desired failure rate MTTF Entire Design 1.68x 10-6 with 6 Drivers on board

AS1116 7 Segment Driver Parameter name Description Value Comments C1 Die complexity 0.0020 3001-10000 gates πT Temperature coeff. 0.98 operating at 85 C C2 Packaging Failure coeff. 0.011 28-pin SMD πE Environmental Factor 2.0 Ground, fixed πQ Quality Factor 10.0 Commercial part πL Learning Factor 1.0 > 2 years ℷP Reliability 0.240 MTTF Entire Design 1.2 x 10-6 5 drivers on the board