Introduction Medical devices must be designed with proper isolation of patients from earth. For that reason all medical products have floating circuits. This means that the circuit ground is isolated from the earth ground. ESD protection in floating circuits with isolated grounds can be very challenging. Sometimes conventional ESD protection methods may not work. It is … [Read more...]
About the Author
Aziz Yuldashev
Aziz is an EMC engineer with a focus on the medical industry. He graduated from Seattle University with a bachelors degree in electrical engineering and a minor in abstract math and physics. Aziz is a member of the Seattle IEEE EMC society and the Tau Beta Pi engineering honors society. Aziz's experience covers the following: consulting engineers on design for EMC, testing and troubleshooting EMC issues on existing designs, consulting on/writing EMC test plans and protocols, consulting on establishing internal EMC standards, consulting on creating risk analyses and establishing essential performance criteria. Contact him at aziz.yulda@gmail.com.
The Importance of Layout in ESD Suppressing Diodes
ESD protection of sensitive electronics via transient voltage suppression (TVS) diodes is becoming a common circuit technique across industries. Signal lines in a circuit that are accessible to humans by touch (such as USB, HDMI, etc.) require ESD protection on all sensitive signal lines that are input to some IC’s. Placement of the ESD protection diodes on the circuit board … [Read more...]
Troubleshooting EFT
EFT Phenomenon Recently I tested a medical device for EFT susceptibility. The requirement is that the medical device must be immune to EFT bursts generated per IEC 61000-4-4. Per this standard EFT bursts are applied in four steps. For level 4, steps 1 and 2 are +/-2kV at 5kHz, and steps 3 and 4 are +/-2kV at 100kHz. For each step, these bursts are applied at 300ms interval for … [Read more...]
T-Filters, Transmission Lines and EMC
Have you ever had a signal integrity issue that did not have its toll on EMC? If you did then you should consider yourself lucky to have avoided this nightmare. I. Situation: An I2S bus master clock driver is set to 12.288MHz and run at 3.3V. Drive strength is at 50-Ohms. Rise time is at 2ns. Fall time is at 2ns. The driver is located on the “master board” and the bus … [Read more...]
