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USB2.0 interface esd protection scheme

Categories: SolutionsStars: 3StarsVisit: -Release time: 2011-05-07 09:44:00
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With the rapid development of modern society, we rely on electronic equipment is growing. The modern computer more and more of the low power of logic chip, because the dielectric breakdown and MOS bipolar reverse "current restriction, make these logic chips are very sensitive to ESD. Most USB integrated circuits are based on CMOS technology to design and manufacture, this cause them to ESD caused damage is very sensitive, in addition, USB port is hot plug and play system, vulnerable user or air discharge by caused by impact. The ESD Users in the swaps any USB peripherals are possible to produce ESD.


In the distance the several inches of conductive position can produce air discharge. Electrostatic can damage the USB interface, integrated circuit fault caused by USB the worst is produced in electronic system in double data bits. The damage caused by electronic equipment fault and the "rigid damage" or components damage. Although for rigid damage we can easily replace the components and make the system failure again back on track, but, if into happened "soft damage" (CMOS device performance relegation), this system will continually produce irregular data bits, to spend hours for any troubleshooting, and relies on repeat tests also difficult to find a system abnormalities, therefore the ESD protection against USB devices is imminent.

ESD components should not only meet the above mentioned ESD industry standard, also involved in the high-speed data transmission using can work with advanced semiconductor devices. So to protect the traditional methods of the serial port in the USB applications will be obsolete or invalid.

Understand the nature of the ESD protection USB devices, will help to clear the semiconductor devices for USB applications necessary characteristics:

1. Low capacitance (< 5pf), in order to reduce high speed USB2.0 (480Mbps, rate of signal attenuation).

2. Nadia work fast response time (in seconds), can be in ESD pulse rising fast time protection USB devices.

3. Low leakage current, to reduce the power consumption under normal work.

4. Solid durable, repeatability of ESD cases in still intact.

5. Integration is high, small area encapsulation.

PJSR05 (PSR05)

1. Low ground-clamp voltage: VRWM = 5V

2. Very low junction: Cj = 5pF

3. Reverse leakage current small: IRWM = 5 muon A

4. Fast response speed: PS

5. Peak pulse power 350W (tp = 8/20 maximum tire-road friction coefficient s)

6. Can be duplicated, small size SOD - 143