1. Reliability and Safety Analysis
Ryan Pawling Team 3

2. 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

3. 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

4. Components Chosen for Analysis
TI LM2675 Voltage Regulator
Atmel AT32UC3B Microcontroller
Omron W2RV004RM RGB LED Driver
AS Segment Driver

5. 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

6. LM2675M Voltage Regulator Parameter name Description Value Comments C1
Die complexity
0.0010
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

7. 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

8. Questions

9. Omron W2V004RM RGB LED Driver
Parameter name
Description
Value
Comments C1
Die complexity
0.0020
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

10. AS1116 7 Segment Driver Parameter name Description Value Comments C1
Die complexity
0.0020
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