Systems Effectiveness Associates, Inc.
20 Vernon Street
Norwood, MA 02063
Phone: 781-762-9252
Fax: 781-769-9422
E-mail: info@sea-co.com
     
 

Reliability Analysis


Reliability Prediction Tool
Tool for Integrating Device Test Data
into Telcordia SR-332 Reliability Predictions
Developed by Jeff Clark. A downloadable version is available by going to www.channel1.com/users/ieee/home.html and then clicking on "Chapter Resources".

Device Data
Input Parameter Symbol Value Units
Black Box Steady-State Failure Rate λBB FIT
Generic Failure Rate λG FIT
Quality Factor πG -
Use Temperature Tuse °C
Use Voltage Vuse V
Activation Energy Ea eV
Voltage Stress Exponent Factor β -
 
Burn-In Data
Input Parameter Symbol Value Units
Burn-In Time per Device tb,d hours
Burn-In Temperature Tburn °C
 
Output Parameter Symbol Value Units
Burn-In Temperature Accelleration Factor Ab,d   V
Ab,d = Ln((Ea ÷ 0.00008617) * (1 ÷ (273 + Tuse)-1 ÷ (273 + Tburn)))
Effective Burn-In Time per Device Te   hours
Te = tb,d * Ab,d
Time Factor W   hours
If(T1 > 10000){ T1 ÷ 4000 } else{ If(T1 + Te) >= 10000) (T1 + Te)^0.25 - D22^0.25 else (T1 + Te) ÷ 4000) + 7.5 - Te^0.25 } }
 
Lab Test Data
Input Parameter Symbol Value Units
Devices on Test N0 -
Actual Test Time per Device T0 hours
Device Failures n -
Test Temperature Ttest °C
Test Voltage Vtest V
Confidence Level on Test Failure Rate Tburn %
 
Output Parameter Symbol Value Units
Test Temperature Acceleration Factor AFt   -
AFt  = Ln((Ea ÷ 0.00008617) * (1 ÷ (273 + Tuse)-1 ÷ (273 + Ttest)))
Test Voltage Acceleration Factor AFv   -
AFV = Exp(β(Vtest - )
Effective Test Time per Device T1   hours
T1 = T0 * AFT * AFV
 
Results
Output Parameter Symbol Value Units
Predicted Failure Rate λBB   FIT
λBB
Test Failure Rate λtest   FIT
λtest =(n ÷ (N0 * T1)) * 10 ^ 9
Upper Confidence Limit on Test Failure Rate λUCL   FIT
(ChiInv(1 - (CL ÷ 100),2 * (n + 1)) ÷ (2 * N0 * T1)) * 10 ^ 9
Integrated Failure Rate λSS   FIT
If(tb,d <> 0){
    ((2 + n) * λBB) ÷ (2 + 0.000004 * N0 * W * πQ * λG)
}
else{
    If(T1 <= 10000) {
        ((2 + n) * λBB) ÷ (2 + 0.000004 * N0 * (T1 ^ 0.25) * πQ * λG)
    }
    else{
       ((2 + n) * λBB) ÷ (2 + (30000 + T1) * N0 * πQ * λG * 10 ^ -9)))
    }
}