Usb Esd Component Selection Guidelines; Usb 2.0 Esd Protection; Circuit Diagram Of Direct Injection Method; Tested Sensitive Nets - Intel Quark SoC X1000 Design Manual

Figure 81.

Circuit Diagram of Direct Injection Method

Table 60.

Tested Sensitive Nets

Rtc_Rst
25M Xtal_Out
platform_s5_pwrok
Dram_Rst#
platform_s3_pwrok
platform_s0_1p0_pwrok
platform_s0_1P5_pwrok
18.3

USB ESD Component Selection Guidelines

18.3.1

USB 2.0 ESD Protection

USB components and ICs are heavily subjected to frequent human contact due to its
hot plugging usage model nature where there is a high frequency of insertion and
removal of various USB devices from the USB ports. As a result, USB ports are easily
exposed to ESD strikes from the human body that can destroy both the USB host and
devices on the platform. ESD discharges from human contact could easily go up to
~35kV under extreme cases; therefore USB ports need to be protected.
There are currently a vast variety of ESD protection devices that are readily available in
the market such as Metal Oxide Varistors (MOVs), Zener Diode, Transient Voltage
Suppressor (TVS), Polymer devices and dual rail clamp diodes. Classic USB (1.0/1.1)
provided ESD suppression using in line ferrites and capacitors that formed a low pass
filter. This technique doesn't work for USB 2.0 due to the much higher signal rate of
high-speed data. With 480Mbps of data rate, USB 2.0 is very sensitive to parasitic
capacitance in it's signal path. A tiny amount of parasitic capacitance in the pF range
could distort USB signal, possibly causing the USB signal to fail and devices not working
properly. In order to meet the stringent requirement on device capacitive load, the Dual
Rail Clamp Diodes, which have the lowest capacitance among the ESD protection
devices, is found to be the best option for USB 2.0 ESD protection.
circuitry of a dual rail clamp diode.
®
Intel Quark™ SoC X1000
PDG
134
Net Name
Xtal
Xtal
PM
CPU
PM
PM
PM
®
Intel Quark™ SoC X1000—Electrostatic Discharge (ESD)
From To
SOC Reboot
SOC Reboot
SOC Reboot
DDR3 Reboot
SOC Reboot
SOC Reboot
SOC Reboot
Typical Symptoms
Figure 82 shows the
June 2014
Order Number: 330258-002US