[ECU Testing] Optimization of noise countermeasures through waveform analysis of DC power supply lines of on-board electronic components

About 80% of system failures are related the power supply of on-board electronic components

The range of allowable voltage will only decrease along with the reduction of voltage in line with the trend of low power consumption. Meanwhile, causes of power source noise are increasing due to a growing number of mounted electronic components, and major LSI manufacturers are saying that malfunction caused by a superimposed noise on a low-voltage driven power line has become a serious problem. In recent years, it has become necessary to have power supply noise evaluation of ± several millivolts to several tens of millivolts full-stop.

A few millivolts are visible with an oscilloscope!

Have you given up on observing the power line noise with an oscilloscope?

Keysight’s N7020A power rail probe is specialized for observing power supply lines.

Power supply waveform of several millivolts becomes clearly visible by combining it with

the already low-noise S-series oscilloscope. This will also reveal very low noise that has been hidden by the noise.

Supporting cost reduction by optimizing bypass capacitors

Do not randomly place bypass capacitors just to solve noise issues. It is important to place the minimum necessary number of bypass capacitors with the appropriate capacity at the appropriate locations.

If the cause of unstable operation is hidden behind the noise floor of the measuring instrument, the effect of the countermeasure parts cannot be checked, and the designer might have to rely just on intuition to minimize or avoid such problems. A reliable design and test solution is better than intuition, and a low-noise measurement environment allows you to visualize the waveform at issue and the effect of the measurement.

Bypass capacitors were added to reduce the noise of the power supply of DDR memory due to unstable operation of the DDR memory. Conventional measurement methods could not provide any information on whether countermeasures helped reduce noise from read/ write operations. With the power supply noise analyzer, the positive effects of the countermeasures could be confirmed.