AF

AFT AFV

×

=

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

Months

AF 1000 h

×

12 months 24 h

365.25 days

×

(

)

×

=

/

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

VCC

maxVop with Vicm

VCC 2

=

=

/

The long term drift parameter (ΔVio), 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

∆Vio

Viodrift

month s

(

)

=

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

5.4

PCB layouts

For correct operation, it is advised to add 10 nF decoupling capacitors as close as possible to the power supply

pins.

5.5

Macromodel

Accurate macromodels of the LMC7101 device are available on the STMicroelectronics’ website at: www.st.com.

These models are a trade-off between accuracy and complexity (that is, time simulation) of the LMC7101

operational amplifier. They emulate the nominal performance of a typical device within the specified operating

conditions mentioned in the datasheet. They also help to validate a design approach and to select the right

operational amplifier, but they do not replace on-board measurements.

LMC7101

PCB layouts

DS13567 - Rev 1

page 12/19