DPPM sample size calculator

Given a certain number of known failures and your sample size, the DPPM calculator can give you the estimated defective parts per million (DPPM) with a certain degree of confidence. Typical value for confidence level is 60 percent.


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Purpose

For a specified Chi-square confidence level, observed or assumed number of fails and Sample size, the calculator provides failure fraction expressed in terms of 'defective parts per million'.

Equation


\[\begin{aligned} \mathbf{DPPM} = 10^6 * \frac{ \mathbf{CHISQ.INV} ( {\mathbf{CL}, 2* \mathbf{fails} + 2}) }{2 * SS} \\ \end{aligned} \]

DPPM - Defective Parts per million

CL - Confidence Level represented as a decimal

SS - Sample size

Fails - Number of failures in your sample size

Important Limitations on Use of Data

TI provides this data for your convenience. However, there are significant limitations of its usefulness as an indicator of how TI parts (including related software) may perform when used in various applications.

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