Today’s high speed communication interfaces are built using a differential mode. (see figure 1)
To speed up data transmissions, a first approach is to reduce the signal amplitude. The smaller the signal amplitude, the more the single-ended transmission is sensitive to noise. In contrary, a differential transmission uses a pair of lines to transmit signals of an equal amplitude in reverse phase (D+, D-) and receive the differential. This transmission method is less sensitive to the noise our ground effect. Also, the magnetic field around the two lines is cancelled, reducing spurious radiation. For these reasons, the differential transmission mode is used for most high-speed data transmission applications.
Figure 1 : Single ended transmission vs Differential Mode transmission
For high-speed datalines like MIPI DSI or CSI, HDMI TMDS lines or USB superspeed signals, ST has developed a range of Common Mode Filters with integrated ESD protection tailored to reject a wide range of frequency bands (700 MHz LTE, 2.4 GHz Bluetooth, 2.4 and 5 GHz Wi-Fi, to name a few) with a deep level of attenuation.
Designed as RF antenna desense medication in applications where the high-speed differential links generate radiated noise at frequencies of the RF antenna, our common-mode filters are strongly recommended for applications where an RF receiver coexists with a high-speed differential dataline.
Benefits of our common-mode filters with integrated protection:
- Improved ESD clamping thanks to dual clamping structure (ESD diode and serial resistor of inductance)
- Improved receiver sensitivity by removing common mode noise in useful antenna bandwidth
- Space and BOM savings by integrating both the ESD protection diodes and the common mode filter
When subjected to common-mode noise, high-speed differential lines generate unwanted radiated noise. Common-mode filters prevent differential lines from radiating and interfering with other RF signals nearby.
In this video, we explain why it is important to protect against electrostatic discharges. We give a quick demonstration to show exactly what happens when you shoot at a microcontroller with an ESD gun!
During this one-hour webinar, you will learn how to make your electronic system more robust against destructive Electrostatic Discharges (ESD) by using ST ESD Protection components. Agenda : 1) ESD major root causes and EMC standards, 2) ST ESD Protections which can help to protect your application againts ESD, 3) Many real application examples demonstrating where protections play an important role, 4) How to select the best protection for your usecases