LMC6482: About TCVOS

In order to specify the maximum input voltage offset drift, each unit would need to be tested in production final test over temperature, which greatly increases its cost. Since we do not test LMC6482 over temp, we cannot guarantee the maximum drift.  However, we have tested over temperature a large sample size of units and their typical drift of +/-1uV/C represent a one standard deviation (sigma) of  Normal Gaussian distribution.  Based on this info you may self-guarantee the maximum drift by accepting a certain failure rate - see below.

Since offset drift may be as likely positive as negative, its Gaussian distribution is centered around zero, thus μ=0.  However, since we specify TYPICAL value as typ=μ+σ, with μ=0 TYPICAL = 0+σ = σ and therefore, σ=1uV/C.

This means that if you accept 1 out of 370 units NOT meeting the limit (+/-3σ), you should assume the maximum drift spec would be +/-3uV/C.

If this is not acceptable, you must use higher number of sigma:

The maximum drift would be +/-4uV/C (+/-4σ) if you accept that 1 out of 15,787 units will NOT meet this limit.

The maximum drift would be +/-5uV/C (+/-5σ) if you accept that 1 out of 1,744,277 units will NOT meet such limit, etc.