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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
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Isograph Reliability Software
Overview of Prediction Methods
Isograph Reliability Software
MIL-217 F Notice 2
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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
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
Isograph Reliability Software
MIL-217 Categories• Quartz Crystal• Meter, Panel• Miscellaneous• Connection• Connector, General• Connector, Socket• Alpha-Numeric Display• Micro, GaAs Digital• Bubble Memory
Isograph Reliability Software
Mil-217 Variable Wirewound Resistor
EQVRTAPSbp
))273
273(exp()358
273exp(0062.0 5
TSTb
792.025
)( 23
TAPSTAPS
N
Isograph Reliability Software
Mil-217 Variable Wirewound Resistor
R= 1.0 for 10 to 2K ohms, 1.4 for >2K to 5K ohms and 2.0 for >5K to 20K ohmsApplied
Voltage/RatedVotage
V
0 to 0.1 1.10>0.1 to 0.2 1.05>0.2 to 0.6 1.00>0.6 to 0.7 1.10>0.7 to 0.8 1.22>0.8 to 0.9 1.40>0.9 to 1.0 2.00
Isograph Reliability Software
Mil-217 Variable Wirewound ResistorQuality
QS 0.02R 0.06P 0.2M 0.6
MIL-R-27208 3.0Lower 10
EnvironmentE
GB 1.0GF 2.0GM 12NS 6NU 20AIC 5AIF 8AUC 9AUF 15ARW 33SF 0.5MF 18ML 48CL 870
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
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
Isograph Reliability Software
Non-Operating Periods
PartTypes
GroundActive toGroundPassive
AirborneActive toAirbornePassive
AirborneActive toGroundPassive
NavalActive toNavalPassive
NavalActive toGroundPassive
SpaceActive toSpacePassive
SpaceActive toGroundPassive
IntegratedCircuits
0.08 0.06 0.04 0.06 0.05 0.1 0.3
Diodes 0.04 0.05 0.01 0.04 0.03 0.2 0.8… … ………
Isograph Reliability Software
Phased Missions• Phase time length• Environment• Temperature• Operating/Non-operating
Isograph Reliability Software
NSWC Standard• Mechanical Components• Combines statistical data with physics of
failure
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
Isograph Reliability Software
NSWC Categories• Rod or Shaft• Housing or Casing• Compressor
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
Isograph Reliability Software
Overview of RDF 2000 RDF 2000 failure rate is function of :
• Physical characteristics of component• Operating conditions – temperature only
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…”
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
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 workingOR– 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
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
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
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iiy
it
.
1
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
offon
iiy
it
.
1
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
68.0
1).( ii
j
in
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
68.0
1).( ii
j
in
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