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Isograph Reliability Software Overview of Prediction Methods.

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Presentation on theme: "Isograph Reliability Software Overview of Prediction Methods."— Presentation transcript:

1 Isograph Reliability Software Overview of Prediction Methods

2 Isograph Reliability Software MIL-217 F Notice 2

3 Isograph Reliability Software MIL-217 Categories Hybrid IA, Plated Through Holes IA, Surface Mount Tech External Capacitor Micro, EEPROM Micro, Not EEPROM Resistor Diode, Low Frequency Diode, High Frequency Transistor, LF Bipolar Transistor, LF FET Transistor, Unijunction Transistor,HF HP Bipolar Diode, Laser Transistor,HF GaAs FET Transistor,HF Si FET Detector, Isolator, Emit Thyristor, SCR Transistor,LN HF Bipolar Hybrid Layer Laser, Helium/Argon Laser, CO2 Sealed Laser, CO2 Flowing

4 Isograph Reliability Software MIL-217 Categories Laser, NdY/Ruby, Krypton Laser, NdY/Ruby, Xenon Tube, NOT TWT/Magnetron Tube, Travelling Wave Tube, Magnetron Micro, SAW Device Micro, VHSIC/VLSI CMOS Microprocessor, Digital Micro, PLA/PAL Micro, Linear Micro, Digital Micro, GaAs MMIC Transformer Coil Meter, Elapsed Time Synchro/Resolver Motor Relay, Solid State/TD Relay, Mechanical Switch Circuit Breaker Fuse Filter, Electronic Lamp

5 Isograph Reliability Software MIL-217 Categories Quartz Crystal Meter, Panel Miscellaneous Connection Connector, General Connector, Socket Alpha-Numeric Display Micro, GaAs Digital Bubble Memory

6 Isograph Reliability Software Mil-217 Variable Wirewound Resistor

7 Isograph Reliability Software Mil-217 Variable Wirewound Resistor

8 Isograph Reliability Software Mil-217 Variable Wirewound Resistor

9 Isograph Reliability Software Bellcore (Telcordia) TR-332 Issue 6 Steady-state failure rate First year multiplier Methods : –Method I –Method II - Unit –Method II - Devices –Method III(a) - Unit –Method III(a) - Devices –Method III(b) - Unit –Method III(b) - Devices –Method III(c) - Unit

10 Isograph Reliability Software Bellcore Categories Hybrid IC, Digital IC, Gate Arrays, PAL IC, Microprocessor IC, Analog/Linear IC, Static RAM IC, Dynamic RAM IC, ROM/PROM/EPROM Opto-Electronic Device Alpha-Numeric Display Transistor Diode Thermistor Resistor, Fixed Resistor, Variable Resistor, Network Capacitor Inductor Connector Switch Relay Rotating Device Miscellaneous Computer System

11 Isograph Reliability Software Non-Operating Periods

12 Isograph Reliability Software Phased Missions Phase time length Environment Temperature Operating/Non-operating

13 Isograph Reliability Software NSWC Standard Mechanical Components Combines statistical data with physics of failure

14 Isograph Reliability Software NSWC Categories Seal, Static or Gasket Seal, Dynamic Spring, Compression/Ext. Spring, Torsion Washer, Curved Washer, Waved Washer, Belleville Spring, Cantilever Spring, Beam Solenoid Valve, Poppet Valve, Sliding Action Bearing Gear Spline Actuator Pump Shaft Pump Fluid Driver Filter Brake Lining Clutch Lining Electric Motor Brush Electric Motor Winding Fastener

15 Isograph Reliability Software NSWC Categories Rod or Shaft Housing or Casing Compressor

16 Isograph Reliability Software Overview of RDF 2000 Telcordia/MIL-217 failure rate is function of : Physical characteristics of component Operating conditions – temperature and environment Test data (field/laboratory) Component quality

17 Isograph Reliability Software Overview of RDF 2000 RDF 2000 failure rate is function of : Physical characteristics of component Operating conditions – temperature only

18 Isograph Reliability Software Overview of RDF 2000 Why does RDF 2000 ignore environment and quality? Environment “ Observed defects are due to thermo-mechanical constraints on components mounted on PCBs…in studied environments no defect due to shock or vibration was observed…” Quality “… choose manufacturers who have quality best practice…in these conditions no longer necessary to take into consideration quality factors…”

19 Isograph Reliability Software Overview of RDF 2000 Varying operational conditions are considered using multiple phases Phase modes are : –On/off –Permanent/dormant (in storage) Workbench allows up to 5 separate phases Phases applied at the Workbench block level

20 Isograph Reliability Software Overview of RDF 2000 RDF 2000 applies the following factors for considering the effects of temperature : The effect of operating the component at a particular temperature whilst it is switched on (PI_t). The effect (PI_n) of : –Varying ambient temperature when the component is in storage or permanently working OR –The temperature rise/fall when the component is cycled between switched on and switched off. Both PI_t and PI_n are summed over all the phases

21 Isograph Reliability Software RDF 2000 Example Consider single phase, 100% permanently working Data required for block: –Tae, outside ambient temperature –Tal, ambient temperature around card –Tac, card (PCB) temperature –dT, variation in outside ambient temperature –N, number of thermal cycles per year

22 Isograph Reliability Software RDF 2000 Example Calculate PI_t sum Calculate junction temperature based on the component power, thermal resistance and the card temperature. Eg Tj = Tac + deltatj Use the junction temperature to look up PI_t Repeat this for each phase Sum PI_t over the phases

23 Isograph Reliability Software RDF 2000 Example For example consider diode with Tac = 35, deltatj = 40 hence Tj = 75. From p 36 of standard look up PI_t as 4.4. Thus Pi_t sum = 4.4 * 100 / 100 = 4.4

24 Isograph Reliability Software RDF 2000 Example Calculate PI_n sum Use the number of cycles per year calculate PI_n: –<= 8760 cycles per year then PI_n = N ^ 0.76 –> 8760 cycles per year then PI_n = 1.7 * N ^ 0.60 Calculate deltati: –For on/off phase then deltati = (deltatj/3 + Tac – tae –For a permanently on or dormant phase then deltati = dT Sum PI_n and deltati over the phases

25 Isograph Reliability Software RDF 2000 Example For example consider permanently working diode with N = 12000 cycles per year and dT = 15. PI_n = 1.7 * 12000^0.60 = 476 Deltati = 15 ^ 0.68 = 6.3 Thus PI_n sum = 476 * 6.3 = 2999

26 Isograph Reliability Software RDF 2000 Example Simplified form of failure rate equation for diode is : (Die base failure rate) * PI_t sum + 2.75e-3 * (package base failure rate) * PI_n sum So typical example using values calculated before: = 0.7 * 4.4 + 2.75e-3 * 2.0 * 2999 = 19.57


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