Friday, March 20, 2020

Estimating Product life Span

To predict the lifetime of a product, manufacturers usually conduct accelerated temperature & Humidity tests. We usually conduct the accelerated test under conditions that are much more severe than the actual operating conditions and record test hours, and time-to-failure. Then we estimate/ calculate the product lifespan using Peck's Power Law.

In the below example, the estimated lifetime of the product under test is 12 months if it survives for 96 hours at 80 °C with 90% RH. Assuming the product's normal upper operating limit of 40 °C and 50% RH, we have got acceleration factor of 92.48.


Digital filtering technique , ADC Filter


A digital filter system usually consists of an analog-to-digital converter (ADC) to sample the input signal, followed by a microprocessor and some peripheral components such as memory to store data and coefficients of the filter, etc.

Program Instructions (software) running on the microprocessor implement the digital filter by performing the necessary mathematical operations on the numbers received from the ADC.

Here is a simple digital filter that identifies and rejects transient response signals. It returns the average of the best two samples of the last three. The third sample is discarded.

Algorithm:
1. Calculate the average of the last 3 samples
2. Identity the sample furthest from the mean value (which is the outlier)
3. Discard the outlier and average the remaining two samples
4. Returns float value of the averaged data (y(i)).



Designing Thermal Vias

Enhancing thermal transfer for FR-4 PCBs can be achieved cost-effectively by incorporating thermal vias and plated through-holes (PTH) betwe...