Reliability Report

AOS Semiconductor
Product Reliability Report
AO4771,
rev A
Plastic Encapsulated Device
ALPHA & OMEGA Semiconductor, Inc
www.aosmd.com
1
This AOS product reliability report summarizes the qualification result for AO4771. Accelerated
environmental tests are performed on a specific sample size, and then followed by electrical test
at end point. Review of final electrical test result confirms that AO4771 passes AOS quality and
reliability requirements. The released product will be categorized by the process family and be
routine monitored for continuously improving the product quality.
Table of Contents:
I.
II.
III.
IV.
Product Description
Package and Die information
Reliability Stress Test Summary and Results
Reliability Evaluation
I. Product Description:
AO4771 uses advanced trench technology to provide excellent RDS(ON) and low gate charge. A
Schottky diode is provided to facilitate the implementation of a bidirectional blocking switch,or for
"standard buck" DC-DC conversion applications.
Details refer to the datasheet.
II. Die / Package Information:
Process
Package Type
Lead Frame
Die Attach
Bond
Mold Material
Moisture Level
AO4771
Standard sub-micron
30V P-Channel MOSFET
SOIC-8
Bare Cu
Ag Epoxy
Cu & Au Wire
Epoxy resin with silica filler
Level 1
2
III. Reliability Stress Test Summary and Results
Test Item
Test Condition
Time Point
Total
Sample
Size
Number
of
Failures
Reference
Standard
HTGB
Temp = 150°C ,
Vgs=100% of Vgsmax
168 / 500 /
1000 hours
924 pcs
0
JESD22-A108
HTRB
Temp = 150°C ,
Vds=80% of Vdsmax
168 / 500 /
1000 hours
924 pcs
0
JESD22-A108
MSL
Precondition
168hr 85°C / 85%RH +
3 cycle reflow@260°C
(MSL 1)
-
4158 pcs
0
JESD22-A113
HAST
130°C , 85%RH,
33.3 psia,
Vds = 80% of Vdsmax
96 hours
924 pcs
0
JESD22-A110
H3TRB
85°C , 85%RH,
Vds = 80% of Vdsmax
1000 hrs
693 pcs
0
JESD22-A101
Autoclave
121°C , 29.7psia,
RH=100%
96 hours
924 pcs
0
JESD22-A102
Temperature
Cycle
-65°C to 150°C ,
air to air,
250 / 500
cycles
924 pcs
0
JESD22-A104
HTSL
Temp = 150°C
1000 hrs
693 pcs
0
JESD22-A103
Note: The reliability data presents total of available generic data up to the published date.
IV. Reliability Evaluation
FIT rate (per billion): 1.91
MTTF = 59839 years
The presentation of FIT rate for the individual product reliability is restricted by the actual burn-in
sample size. Failure Rate Determination is based on JEDEC Standard JESD 85. FIT means one
failure per billion hours.
2
9
Failure Rate = Chi x 10 / [2 (N) (H) (Af)] = 1.91
9
MTTF = 10 / FIT = 59839 years
Chi²= Chi Squared Distribution, determined by the number of failures and confidence interval
N = Total Number of units from burn-in tests
H = Duration of burn-in testing
Af = Acceleration Factor from Test to Use Conditions (Ea = 0.7eV and Tuse = 55°C)
Acceleration Factor [Af] = Exp [Ea / k (1/Tj u – 1/Tj s)]
Acceleration Factor ratio list:
55 deg C
70 deg C
85 deg C
100 deg C
115 deg C
Af
259
87
32
13
5.64
Tj s = Stressed junction temperature in degree (Kelvin), K = C+273.16
Tj u =The use junction temperature in degree (Kelvin), K = C+273.16
k = Boltzmann’s constant, 8.617164 X 10-5eV / K
130 deg C
150 deg C
2.59
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