Reliability Report

AOS Semiconductor
Product Reliability Report
AO7405/AO7405L,
rev B
Plastic Encapsulated Device
ALPHA & OMEGA Semiconductor, Inc
495 Mercury Drive
Sunnyvale, CA 94085
U.S.
Tel: (408) 830-9742
www.aosmd.com
Feb 15, 2006
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This AOS product reliability report summarizes the qualification result for AO7405/AO7405L.
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 AO7405/AO7405L
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.
V.
Product Description
Package and Die information
Environmental Stress Test Summary and Result
Reliability Evaluation
Quality Assurance Information
I. Product Description:
The AO7405 uses advanced trench technology to provide excellent RDS(ON), low gate charge, and
operation with gate voltages as low as 2.5V, in the small SOT363 footprint. It can be used for a
wide variety of applications, including load switching, low current inverters and low current DC-DC
converters. Standard Product AO7405 is Pb-free (meets ROHS & Sony 259 specifications).
AO7405L is a Green Product ordering option. AO7405 and AO7405L are electrically identical.
Absolute Maximum Ratings TA=25°C unless otherwise noted
Parameter
Symbol
Maximum
Units
Drain-Source Voltage
VDS
-30
V
Gate-Source Voltage
VGS
±12
V
ID
-1.6
Continuous
Drain Current
TA=25°C
TA=70°C
Pulsed Drain Current
Power
Dissipation
TA=25°C
TA=70°C
Junction and Storage
Temperature Range
Thermal Characteristics
Parameter
Maximum JunctionT ≤ 10s
to-Ambient
Maximum JunctionSteadyto-Ambient
State
Maximum JunctionSteadyto-Lead
State
-1.3
IDM
A
-10
0.625
PD
TJ, TSTG
Symbol
RθJA
RθJL
0.4
W
-55 to 150
°C
Typ
Max
160
200
180
220
130
160
Units
°C/W
2
II. Die / Package Information:
Process
AO7405
AO7405L (Green Compound)
Standard sub-micron
Standard sub-micron
low voltage P channel process low voltage P channel process
Package Type
Lead Frame
Die Attach
Bondwire
Mold Material
Flammability Rating
Backside Metallization
Moisture Level
SC-70 3L
Alloy 42 Ag spot
Silver epoxy
1.3mils Au wire
Epoxy resin with silica filler
UL-94 V-0
Ti / Ni / Ag
Up to Level 1 *
SC-70 3L
Alloy 42 Ag spot
Silver epoxy
1.3mils Au wire
Epoxy resin with silica filler
UL-94 V-0
Ti / Ni / Ag
Up to Level 1*
Note * based on info provided by assembler and mold compound supplier
III. Result of Reliability Stress for AO7405 (Standard) & AO7405L (Green)
Test Item
Test Condition
Time Point
Lot Attribution
Total
Sample size
Solder
Reflow
Precondition
Standard: 1hr PCT+3
cycle reflow@260°c
Green: 168hr 85°c/85RH
+3 cycle reflow@260°c
Temp = 150°c,
Vgs=100% of Vgsmax
0hr
Standard: 4 lots
Green: 4 lots
1265 pcs
0
4 lots
328 pcs
0
HTGB
168 / 500
hrs
(Note A*)
Number of
Failures
77+5 pcs / lot
1000 hrs
HTRB
Temp = 150°c,
Vds=80% of Vdsmax
168 / 500
hrs
4 lots
(Note A*)
328 pcs
0
77+5 pcs / lot
1000 hrs
HAST
Pressure Pot
130 +/- 2°c, 85%RH,
33.3 psi, Vgs = 80% of
Vgs max
121°c, 29.7psi,
RH=100%
100 hrs
Standard: 4 lots
Green: 4 lots
440 pcs
0
50+5 pcs / lot
96 hrs
(Note B**)
Standard: 4 lots
Green: 3 lots
385 pcs
0
50+5 pcs / lot
Temperature
Cycle
-65°c to 150°c,
air to air, 0.5hr per cycle
250 / 500
cycles
(Note B**)
Standard: 4 lots
Green: 4 lots
440 pcs
0
50+5 pcs / lot
(Note B**)
DPA
CSAM
Internal Vision
Cross-section
X-ray
NA
5
5
5
5 pcs
5 pcs
5 pcs
0
NA
5
5 pcs
0
3
Bond
Integrity
Room Temp
150°c bake
150°c bake
0hr
250hr
500hr
40
40
40
40 wires
40 wires
40 wires
0
Solderability
230°c
5 sec
15
15 leads
0
Die shear
150°c
0hr
10
10 pcs
0
Note A: The HTGB and HTRB reliability data presents total of available AO7405 and AO7405L
burn-in data up to the published date.
Note B: The pressure pot, temperature cycle and HAST reliability data for AO7405 and AO7405L
comes from the AOS generic package qualification data.
IV. Reliability Evaluation
FIT rate (per billion): 11.7
MTTF = 9757 years
In general, 500 hrs of HTGB, 150 deg C accelerated stress testing is equivalent to 15 years of
lifetime at 55 deg C operating conditions (by applying the Arrhenius equation with an activation
energy of 0.7eV and 60% of upper confidence level on the failure rate calculation). AOS reliability
group also routinely monitors the product reliability up to 1000 hr at and performs the necessary
failure analysis on the units failed for reliability test(s).
The presentation of FIT rate for the individual product reliability is restricted by the actual burn-in
sample size of the selected product (AO7405). Failure Rate Determination is based on JEDEC
Standard JESD 85. FIT means one failure per billion hours.
Failure Rate = Chi2 x 109 / [2 (N) (H) (Af)]
= 1.83 x 109 / [2 (2×164) (168) (258) + 2 (164) (500) (258) + 2 (164) (1000) (258)] = 11.7
MTTF = 109 / FIT = 8.54 x 107hrs = 9757years
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
k = Boltzmann’s constant, 8.617164 X 10-5eV / K
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V. Quality Assurance Information
Acceptable Quality Level for outgoing inspection: 0.1% for electrical and visual.
Guaranteed Outgoing Defect Rate: < 25 ppm
Quality Sample Plan: conform to Mil-Std-105D
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