TSX921 datasheet(19/32 Pages) STMICROELECTRONICS

19 / 32 page

TSX920, TSX921, TSX922, TSX923

Application information

DocID024310 Rev 4

19/32

k is the Boltzmann constant (8.6173 x 10

-5 eV.K-1)

TU is the temperature of the die when VU is used (K)

TS is the temperature of the die under temperature stress (K)

The final acceleration factor, AF, is the multiplication of the voltage acceleration factor and

the temperature acceleration factor (Equation 4).

Equation 4

AF is calculated using the temperature and voltage defined in the mission profile of the

product. The AF value can then be used in Equation 5 to calculate the number of months of

use equivalent to 1000 hours of reliable stress duration.

Equation 5

To evaluate the op amp reliability, a follower stress condition is used where VCC is defined

as a function of the maximum operating voltage and the absolute maximum rating (as

recommended by JEDEC rules).

The Vio drift (in µV) of the product after 1000 h of stress is tracked with parameters at

different measurement conditions (see Equation 6).

Equation 6

The long term drift parameter (ΔV

io), estimating the reliability performance of the product, is

obtained using the ratio of the Vio (input offset voltage value) drift over the square root of

the calculated number of months (Equation 7).

Equation 7

Where Vio drift is the measured drift value in the specified test conditions after 1000 h

stress duration.

Months

1000 h

12 months

24 h

365.25 days

maxV

op with Vicm

∆V

iodr ift

month s

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