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DATASHEET
SEP 05, 2007
SFS5 Series AC-DC Converter Compact Miniature Type
With Your Electronics POWERPLAZA
www.powerplaza.co.kr
Calculating Reliable Values of MTBF
1. Calculating method
Calculated based on part count reliability projection of MIL-HDBK-217F Individual failure rates λg is
given to each part and MTBF (Mean Time Between Failure) is calculated by the count of each part.
<Formula>:
n
MTBF = 1/ λepuip = 1/ (∑Ni(λG∏Q)i
*10^
6 (Hours)
i=1
λequip
: Total Equipment Failure Rate (Failure/10^
6Hours)
λG
: Generic Failure Rate for The ith Generic Part (Failure/ 10^
6Hours)
∏Q
: Generic Quality Factor for The ith Generic Part (∏Q=1)
Ni
: Quantity of ith Generic Part
n
: Number of Different Generic Part Categories
2. MTBF Values
MTBF ≒484,937(Hours)
PART
Number
Failure Rate
Failure
Rate*n
Remark
n
λG(F/T)
λG×n(F/T)
Logic IC
1
0.01500
0.01500
Separate
Transistor, FET
1
0.09900
0.09900
Separate
Diode
6
0.02200
0.13200
Voltage Regulator
1
0.02400
0.02400
Photo-coupler
1
0.07000
0.07000
Diode Bridge
1
0.06600
0.19800
*3
Ele-capacitor
3
0.01900
0.05700
Ceramic Capacitor
1
0.02600
0.02600
MLCC
7
0.05300
0.37100
Choke coil
1
0.00022
0.00022
Switching trans
1
0.00420
0.00420
Line Filter
2
0.00440
0.00880
Resistor Chip
7
0.01600
0.11200
Connector
5
0.05200
0.26000
Reflow soldering
45
0.00014
0.00630
Flow soldering
37
0.00780
0.28860
PCB
1
0.37000
0.37000
SMT
Fuse
1
0.02000
0.02000
Total Equipment Failure Rate λG×n(F/T)
2.06212
MTBF = 10^
6 / λG(F/T)
484937.831
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