Datasheet

Application information TSX56x, TSX56xA
16/28 DocID023274 Rev 4
4.4 Long term input offset voltage drift
To evaluate product reliability, two types of stress acceleration are used:
• Voltage acceleration, by changing the applied voltage
• Temperature acceleration, by changing the die temperature (below the maximum
junction temperature allowed by the technology) with the ambient temperature.
The voltage acceleration has been defined based on JEDEC results, and is defined using
Equation 2.
Equation 2
Where:
A
FV
is the voltage acceleration factor
β is the voltage acceleration constant in 1/V, constant technology parameter (β = 1)
V
S
is the stress voltage used for the accelerated test
V
U
is the voltage used for the application
The temperature acceleration is driven by the Arrhenius model, and is defined in Equation 3.
Equation 3
Where:
A
FT
is the temperature acceleration factor
E
a
is the activation energy of the technology based on the failure rate
k is the Boltzmann constant (8.6173 x 10
-5
eV.K
-1
)
T
U
is the temperature of the die when V
U
is used (K)
T
S
is the temperature of the die under temperature stress (K)
The final acceleration factor, A
F
, is the multiplication of the voltage acceleration factor and
the temperature acceleration factor (
Equation 4).
Equation 4
A
F
is calculated using the temperature and voltage defined in the mission profile of the
product. The A
F
value can then be used in Equation 5 to calculate the number of months of
use equivalent to 1000 hours of reliable stress duration.
A
FV
e
β V
S
V
U
–()⋅
=
A
FT
e
E
a
k
------
1
T
U
------
1
T
S
------–
⎝⎠
⎛⎞
⋅
=
A
F
A
FT
A
FV
×=