- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄379503 > UPD7720AC (NEC Corp.) QUARTERLY MICROPROCESSOR/MICROCOMPUTER RELIABILITY REPORT PDF資料下載
參數(shù)資料
| 型號： | UPD7720AC |
| 廠商： | NEC Corp. |
| 英文描述： | QUARTERLY MICROPROCESSOR/MICROCOMPUTER RELIABILITY REPORT |
| 中文描述： | 季報微處理器/微機可靠性報告 |
| 文件頁數(shù)： | 3/12頁 |
| 文件大?。?/td> | 59K |
| 代理商： | UPD7720AC |
NEC Electronics Inc.
Roseville Manufacturing
3
Failure Rate Prediction
This report contains reliability test results of all microprocessor
devices assembled in NEC Roseville that were subjected to
routine Monitor Reliability Testing (MRT). It also contains
failure rate predictions for these devices, calculated using the
Arrhenius method shown below.
This report will be updated in September 1998.
When predicting the failure rate at a certain temperature from
accelerated life test data, various values of activation energy,
corresponding to failure mechanisms, should be considered.
This procedure is done whenever exact causes of failures are
known by performing failure analysis. In some cases, however,
an average activation energy is assumed in order to accomplish
a quick first-order approximation. NEC assumes an average
activation energy of 0.7 eV for CMOS-4 and lesser
technologies and 0.45 eV for CMOS-5 and greater
technologies for such approximations. These average values
have been assessed from extensive reliability test results and
yield a conservative failure rate.
Since life testing at NEC is performed under high-temperature
ambient conditions, the Arrhenius relationship is used to
normalize failure rate predictions at a system operation
temperature of 55°C. The Arrhenius model includes the effects
of temperature and activation energy of the failure mechanisms.
This model assumes that the degradation of a performance
parameter is linear with time. The temperature dependence is
taken to be an exponential function that defines the probability
of occurrence.
The Arrhenius equation is:
A =
exp
EA(TJ1
TJ2)
k(TJ1)(TJ2)
(1)
Where:
A
EA
T J1
T J2
k
≡
Acceleration factor
≡
Activation energy
≡
Junction temperature (in K)
≡
Junction temperature (in K)
≡
Boltzmann's constant = 8.62 x 10
5 eV/K
at TA1 = 55°C
at TA2 = 125°C
Because temperature dependence on power dissipation of a
particular device type cannot be ignored, junction temperatures
(TJ1 and TJ2) are used instead of ambient temperatures (TA1
and TA2) . Also, thermal resistance of a particular device
cannot be ignored. These two factors cannot be accounted for
unless junction temperatures are used. We calculate junction
temperatures using the following formula:
TJ = TA + (Thermal Resistance) x (Power Dissipation at TA)
From the high-temperature operating life test results, the failure
rates can be predicted at a 60% confidence level using the
following equation:
L =
X2 105
2T
(2)
Where:
L
X2
≡
Failure rate in %/1000 hours
≡
The tabular value of chi-squared distribution at
a given confidence level and calculated degrees
of freedom (2f + 2, where f = number of
failures)
T
≡
=
T Number of equivalent device hours
(Number of devices) x
(number of test hours) x
(acceleration factor)
Another method of expressing failures is as FIT (failures in
time). One FIT is equal to one failure in 10
9
hours. Since L is
already expressed as %/1000 hours (10
5
failure/hr), an easy
conversion from %/1000 hours to FIT would be to multiply the
value of L by 10
4
.
Example
A sample of 960 pieces was subjected to 1000 hours at 125°C
burn-in. One reject was observed. Given that the acceleration
factor was calculated to be 34.6 using equation (1), what is the
failure rate, normalized to 55°C, using a confidence level of
60% Express the failure rate in FIT.
Solution
For n = 2f + 2 = 2(1) + 2 = 4,
X
2
= 4.046.
Then L =
X
2
10
5
2T
(%/1000H)
=
X
2
10
5
2 (s.s.)(test hrs)(acc. factor)
=
(4.046) 10
5
2(960)(1000)(34.6)
=
0.0061 %/1000H
Therefore, FIT = (0.0061)(10
4
) = 61
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| UPD77210 | 16-BIT FIXED-POINT DIGITAL SIGNAL PROCESSOR |
| UPD77210F1-DA2 | 16-BIT FIXED-POINT DIGITAL SIGNAL PROCESSOR |
| UPD77210GJ-8EN | 16-BIT FIXED-POINT DIGITAL SIGNAL PROCESSOR |
| UPD77213F1-xxx-DA2 | 16-BIT FIXED-POINT DIGITAL SIGNAL PROCESSOR |
| UPD77213GJ-xxx-8EN | 16-BIT FIXED-POINT DIGITAL SIGNAL PROCESSOR |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| UPD7759C | 制造商: 功能描述: 制造商:undefined 功能描述: 制造商:Panasonic Industrial Company 功能描述:IC |
| UPD780023AGB-G43-8EU-X3-A | 制造商:Renesas Electronics Corporation 功能描述: |
| UPD780023AGB-G44-8EU-E3-A | 制造商:Renesas Electronics Corporation 功能描述: |
| UPD780023AGC-107-8BS-A | 制造商:Renesas Electronics Corporation 功能描述:NECUPD780023AGC-107-8BS-A MASK ROM DEVIC |
| UPD780023AGK-C74-9ET-A | 制造商:Renesas Electronics Corporation 功能描述: |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。