Proper derating can mitigate premature wear-out of electronic components in the power circuits. Recommended standard derating factors outlined in IPC-9592B Section 4.3 and Appendix A. Wear out and examples of life estimation for MLCC and aluminum electrolytic capacitors used in filter applications will be discussed

1. Requirements for Power Conversion Devices for the
Computer and Telecommunications Industries
IPC-9592A
Derating Guidance
1
Alessandro A. (Alex) Cervone
Technical Manager – Component Reliability & Engineering
GE Energy – Power Electronics
601 Shiloh Road
Plano, Texas 75074
Applied Power Electronics Conference (APEC)
Orlando, Florida – February 8, 2012

2. Derating Guidance
Proper derating can mitigate premature wear-out of
electronic components in the power circuits.
Recommended standard derating factors outlined in
IPC-9592B Section 4.3 and Appendix A.
Wear out and examples of life estimation for MLCC and
aluminum electrolytic capacitors used in filter applications
will be discussed
2

3. Appendix A - What’s Changed?
3
 MLCC
 Voltage derating from 80% to 90%
 Allow sizes > 1210 if flexible terminations
 Life Estimation per Prokopowicz and
Vaskas (PV Equation)
 Fixed Aluminum Electrolytic
 Add ripple current derating of 80%

4. Appendix A - What’s Changed?
4
 Power MOSFET
 Avalanche allowed for Vds rating below
200V
 Added dv/dt rating
 Power Magnetics
 Derating according to temperature rise

5. MLCC Life Estimation
Structure of MLCC
5
 Ceramic (BaTiO3)
 Electrodes
 PME (Pd)
 BME (Ni)

6. MLCC Life Estimation
Ceramic – Perovskite Crystal
6
 Barium Titanate (BaTiO3)
 Provides highest possible
dielectric constant
 Easy to Manufacture
 Environmental friendly

7. MLCC Life Estimation
Market Demands for Higher Density
7
 Miniaturization and volumetric efficiency
 Thinner dielectric layers
 Higher layer count
 Lower Cost
 Replace Pd with Ni electrodes

8. MLCC Life Estimation
Unintended Consequences
8
 To avoid oxidation of Ni electrodes during
firing, manufacturers must use inert
atmosphere
 Thinner dielectric suffers degradation of
insulation resistance due to
 Voltage stress
 Temperature stress

9. MLCC Life Estimation
Oxygen Vacancy
9
 Oxygen atom may be
removed from lattice
during firing
 Results in an
oxygen vacancy

10. MLCC Life Estimation
Wear-out due to Oxygen Vacancy Migration
10
 Oxygen vacancies are positively charged and tend
to migrate towards the cathode
 Oxygen vacancy migration accelerates with
increased voltage and temperature
 Resultant reduction in insulation resistance (due to
increased charge accumulation and temperature
rise) will lead to a short circuit

11. MLCC Life Estimation
P-V Equation1
11
t1
t2
V2
V1






n
 exp
Ea
K
1
T1
1
T2














Where:
t1 = time to failure under test condition
V1 = voltage under test condition
N = voltage stress exponential
Ea = activation energy of dielectric wear out
k = Baltzmann’s constant
T1 = absolute temperature for test condition
1 Prokopowicz and Vaskas

12. MLCC Life Estimation
HALT Data
12
 In order to use the PV equation, we require some
constants that are determined by accelerating the
wear-out at high temperature and high voltage
(HALT) which must be provided by device
manufacturer.
MPN Type size cap BV Theta n
Test
temp
Test
Voltage
B1
Life
(hrs)
Time to 1%
fail at rated
T/V (yrs)
nnnnnnnnnnnn
nnnnnnn X5R 0805 22 6.3 6.6 4.1 150 13 0.8 1.6
nnnnnnnnnnnn
nnnnnnn X5R 1206 47 6.3 6.6 4.1 150 13 2.2 5
nnnnnnnnnnnn
nnnnnnn X5R 1210 100 6.3 8 5 150 12.6 14 14.3
nnnnnnnnnnnn
nnnnnnn X5R 0603 4.7 6.3 6.6 4.1 150 12.6 1.05 1.9

13. Aluminum Electrolytic Life Estimation
Lx L0 2
T0 Tx
10
 2
T 0 T x
8

V0
Vx






n

Where:
T0 = Max usage temperature
Tx = Capacitor local ambient in use conditions
∆T0 = Core temperature rise at T0 with max ripple current
∆Tx = Core temperature rise at Tx with actual ripple current
L0 = Base lifetime of capacitors (hours)
Lx = Capacitor life to be estimated (hours)
V0 = Capacitor rated voltage
Vx = Actual operating voltage applied to capacitor
n = 4.4 For snap-in type
n = 2 for radial where ΦD≤10mm or L≤20mm
2From Samxon Aluminum Electrolytic Application Guidelines

14. Aluminum Electrolytic Life Estimation
14
 Core temperature is key
to proper lifetime
estimation
 Have manufacture build a
sample with thermo-
couple buried inside core

15. Aluminum Electrolytic Life Estimation
Example
15
25C
Component Description Component Specifications Stress in Application
Estimated
Life
Ref Des Type
Cap.
(uF)
Rated
Voltag
e V0
(V)
Case
Size
ΦDxL
Temp.
Ratin
g T0
(°C)
△T0
(ºC)
Base
Lifetime
L0 (Hrs)
Actual
operating
voltage
Vx (V)
Ambien
t Temp
Tx(°C)
Temper
ature
rising.
△Tx
(°C)
n
Lx
(Hrs)
Lx
(Year
s)
C204 nnnnnnnnnnnn 220 450 25*30 105 5 2000 425 29.12 6.89 4.4
42009
8
48.0
40C
C204 nnnnnnnnnnnn 220 450 25*30 105 5 2000 425 44.25 6.1 4.4
15762
3
18.0
50C
C204 nnnnnnnnnnnn 220 450 25*30 105 5 2000 425 54.77 5.79 4.4 78091 8.9
Test conditions: 230Vac /52V /30.9A

16. Conclusions
16
 Derating electronic components mitigates risk of
premature wear out.
 Lifetime estimation is recommended for MLCC’s,
when used in filter applications (with high RMS
current) - 20○C max due to self heating
 Aluminum electrolytic capacitor core
temperature is key to lifetime estimation

17. References
17
[1] T. Prokopowicz and A. Vaskas, “Research and Development, Intrinsic Reliability, Subminiature
Ceramic Capacitors,” Final Report, ECOM-9705-F, 1969 NTIS AD-864068
[2] Life Calculation of Aluminum Electrolytic Capacitor – Man Yue Electronics Co., LTD