Reliability Report

AOS Semiconductor
Product Reliability Report
AO4854,
rev B
Plastic Encapsulated Device
ALPHA & OMEGA Semiconductor, Inc
www.aosmd.com
This AOS product reliability report summarizes the qualification result for AO4854.
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 AO4854
passes AOS quality and reliability requirements. The released product will be categorized by
the process family and be monitored on a quarterly basis for continuously improving the
product quality.
Table of Contents:
I.
II.
III.
IV.
Product Description
Package and Die information
Environmental Stress Test Summary and Result
Reliability Evaluation
I. Product Description:
The AO4854 uses advanced trench technology to provide excellent RDS(ON) and low gate
charge. The two MOSFETs make a compact and efficient switch and synchronous rectifier
combination for use in DC-DC converters.
-RoHS Compliant
-Halogen-Free
Detailed information refers to datasheet.
II. Die / Package Information:
AO4854
Standard sub-micron
Low voltage N channel
Package Type
SO8
Lead Frame
Cu Alloy
Die Attach
Ag Epoxy
Bonding
Cu wire
Mold Material
Epoxy resin with silica filler
MSL (moisture sensitive level) Level 1 based on J-STD-020
Process
Note * based on information provided by assembler and mold compound supplier
III. Result of Reliability Stress for AO4854
Test Item
Test Condition
Time
Point
MSL
Precondition
168hr 85°c
/85%RH +3 cycle
[email protected]°c
-
HTGB
Temp = 150 °c,
Vgs=100% of
Vgsmax
168hrs
500 hrs
1000 hrs
Lot
Attribution
Total
Sample
size
Number
of
Failures
29 lots
3575pcs
0
JESD22A113
1 lot
308pcs
0
JESD22A108
0
JESD22A108
880pcs
0
JESD22A110
3 lots
(Note A*)
Standard
77pcs / lot
Temp = 150 °c,
Vds=80% of
Vdsmax
168hrs
500 hrs
1000 hrs
HAST
130 °c, 85%RH,
33.3 psi, Vgs =
100% of Vgs max
100 hrs
16 lots
Pressure Pot
121°°c, 29.7psi,
RH=100%
96 hrs
(Note A*)
20 lots
55 pcs / lot
1100pcs
0
JESD22A102
Temperature
Cycle
-65°°c to 150°°c,
air to air
250 / 500
cycles
(Note A*)
29 lots
55 pcs / lot
1595pcs
0
JESD22A104
(Note A*)
55 pcs / lot
HTRB
1 lot
3 lots
(Note A*)
308pcs
77pcs / lot
Note A: The reliability data presents total available generic data up to the published date.
IV. Reliability Evaluation
FIT rate (per billion): 7
MTTF = 15704 years
The presentation of FIT rate for the individual product reliability is restricted by the actual
burn-in sample size of the selected product (AO4854). 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)]
9
= 1.83 x 10 / [2x (2x77x168+6x77x1000) x258] = 7
9
8
MTTF = 10 / FIT = 1.38 x 10 hrs = 15704 years
Chi² = Chi Squared Distribution, determined by the number of failures and confidence interval
N = Total Number of units from HTRB and HTGB tests
H = Duration of HTRB/HTGB 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:
Af
55 deg C
70 deg C
85 deg C
100 deg C
115 deg C
130 deg C
150 deg C
258
87
32
13
5.64
2.59
1
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
-5
K = Boltzmann’s constant, 8.617164 X 10 eV / K