You can use the MIL-HDBK-217 method’s models for components that are not yet modeled in 217Plus. After you derive the MIL-HDBK-217 failure rate, multiply it by the duty cycle of your product to convert the operating hours based failure rate to a calendar hours based failure rate as required by 217Plus.
Note: in 217Plus, Duty Cycle = (power on time in 1 calendar year)/(1 calendar), where 1 calendar year = 8760 hours . For example, if the circuit has power applied 8hrs per day, 365 days per year, the duty cycle is: (8hr/day x 365 days/year)/3860hrs = 0.33
DO NOT use MIL-HDBK-217 models for components that are modeled by 217Plus.
The following are suggested approaches to modelling your components:
1) DIODE TRANSIL
Model: Diode, Low Frequency, Transient Suppressor – and set the quantity to the number of devices in the array
2) ESD PROTECTION DIODE
Model: Diode, Low Frequency, Transient Suppressor – and set the quantity to the number of devices in the array
3) IC, ADC CONVERTER
Model: IC, Linear, Plastic (Also use IC, Linear, Plastic for D/A converters, V/F Converters, etc.)
4) Jumper: JUMPER-2.0/B –TME
Jumpers and wires do not need to be included in a 217Plus analysis.
5) Battery holder for battery CR2032: SN2032SN-LF – Martiex
Model: Connectors, PWB
6) Suppression Filter: NFE61PT472C1H9L – Fernell
This device is a combination of 2 inductors and 1 capacitor. Model it using:
Model 1: Inductor, General (quantity 2)
Model 2: Capacitor, Ceramic (quantity 1)
7) FUSES SMD: BSMD-T1.0A – TME
Model: Use the MIL-HDBK-217 method to develop the failure rate, then multiply the result by the duty cycle of the circuit to provide the failure rate in terms of calendar time.
8) Quartz crystal SMD: QSD12M000 – Maritex
Model: Use the MIL-HDBK-217 method to develop the failure rate, then multiply the result by the duty cycle of the circuit to provide the failure rate in terms of calendar time
9) Quartz Crystal SMD with Capacitor: 12.00M-12SMXR – TME
Model this as two components:
Model 1: Capacitor, Ceramic (quantity 1)
Model 2: Use the MIL-HDBK-217 method to develop the failure rate for the crystal, then multiply the result by the duty cycle of the circuit to provide the failure rate in terms of calendar time
Regards,
Paul Wagner
