The hottest high-performance ESD protection scheme

  • Detail

High performance ESD protection scheme for portable applications

with more functions in portable devices, there are more potential input and output (i/o) channels for electrostatic discharge (ESD) voltage to enter, including keyboard, keys, SIM card, battery charging, USB interface, FM antenna, LCD display, headphone jack, FM antenna and many other places need ESD protection. According to the capacitance and data rate, the ESD protection application fields of portable devices can be divided into three types: high-power, high-speed and very high-speed. The capacitance is greater than 30 PF, between 1 to 30 PF and less than 1 PF, respectively. See Table 1. In order to avoid the sensitivity of oil pollution to the mechanism, it can be seen from this table that the higher the speed, the lower the capacitance is required, because it is more necessary to maintain signal integrity and reduce insertion loss in high-speed applications

Table 1: ESD protection application classification and typical protection products of portable devices (among which the red font is the leading product)

the most effective ESD protection method for portable devices

from the perspective of protection method, a possible choice is to build ESD protection in the chip, but the shrinking CMOS chip has become increasingly insufficient to bear the area required for internal 2 kV ESD protection, so the truly effective ESD protection cannot be fully integrated into CMOS chips. In addition, although efforts in physical circuit design and software design can play some roles, there are always some important circuits that are sensitive and difficult to isolate from the outside, so the most effective ESD protection method is to place protective elements at the connectors or ports of portable devices to clamp the extremely high ESD voltage to a lower voltage, so as to ensure that the voltage will not exceed the breakdown voltage of oxides in integrated circuits (ICS), Protect sensitive IC

under normal working conditions, the external ESD protection components should remain in the inactive state without any impact on the function of the electronic system, which can be achieved by maintaining low current and low capacitance. Under the condition of ESD stress shock or high current shock, the first requirement of ESD protection components is that they must be able to work normally and have a low enough resistance to limit the voltage at the protected point; Secondly, it must be able to act quickly, so that the rise time is lower than the rise time of nanosecond ESD impact

comparison and performance test of external protection components

common external protection components include varistors, polymers and silicon Transient Voltage Suppressors (TVS), which are made of metal oxides, polymers with conductive particles and silicon. The varistor shows high resistance at low voltage, while the resistance will decrease at high voltage. Polymers with conductive particles have high resistance under normal voltage, but when subjected to ESD stress, the small gap between conductive particles will become a gap array, resulting in a low resistance path. TVs is a silicon chip component designed with standard and zener diode characteristics. TVs components are mainly optimized for the requirements of carrying high current with low dynamic resistance. Because TVs components are usually produced in IC mode, we can see a variety of unidirectional, bidirectional and array single-chip products

among these external protection elements, TVs elements have excellent high current conductivity, and can still maintain excellent performance under repeated stress conditions. There is no problem that the performance will decline after the use of other protection elements such as varistors or polymers increases, and the new ESD elements have extremely low capacitance, which is very suitable for ESD protection of high-speed data lines. The higher the speed of application, the more ESD protection is required. State administrative intervention disrupts the normal operation of the market. Components have lower capacitance and lower clamping voltage

Figure 1: on semiconductor integrated silicon ESD protection components have better clamping voltage performance than competitive devices

the electronic system must be able to survive under IEC standard test conditions. In order to make a more direct comparison of the above-mentioned external ESD protection elements, the IEC 8 kV ESD contact discharge pulse is first applied to the varistor, polymer, Anson semiconductor silicon protection element and the silicon competitive device with the closest performance, and the ESD clamping voltage waveform is intercepted by the oscilloscope for comparison. It can be found that the silicon ESD protection element of Anson semiconductor has a much lower clamping voltage, It is not only better than passive components such as varistors and polymers, but also better than silicon competitive devices with the closest performance. See Figure 1

in addition, portable devices may suffer from multiple ESD voltage stresses, which is particularly prominent in northern China. Because the performance of external protection components under various ESD stress conditions is still important, which directly determines the reliability of portable products. Therefore, protective elements such as varistors, polymers and silicon ESD diodes can also be tested under tesec DC test conditions. Each element is applied with a total of 2000 15 kV contact discharge ESD pulses (1000 in the positive and negative directions), and the time interval between each pulse is 0.1 seconds. The test results shown in Table 2 show that the silicon set apple of Anson semiconductor, as the king of ESD protection components in the new era, still passes the tension deviation test and 100000 fatigue tests (equivalent to 20 years of operation) of the spring compensator under multiple stress conditions. The tension deviation of the spring compensator within the life cycle is 5%, that is, 95% of the compensation effect, but maintains excellent performance, while the competitive devices are either damaged or the performance degradation is serious. Performance comparison of ESD external protection components after multiple stresses

overview of high-performance ESD external protection components of ansenmey semiconductor

as shown in Table 1, ansenmey Semiconductor provides a series of high-performance silicon ESD protection components for high-power, high-speed and extremely high-speed applications of portable devices to meet different application needs. Among them, the esd11l, esd11n, nup4016 (for very high-speed applications) and esd11b, nup4xxxp5 (for high-speed applications) of Anson semiconductor are the leading products in the industry today

for example, nup4016 has an ultra-low capacitance of 0.5 pf per i/o line, which is very suitable for protecting high-speed interfaces such as universal serial bus (USB) 2.0 high speed (480 Mbps) and high-definition multimedia interface (HDMI) (1.65 Gbps). Esd11l5.0d integrates the ultra-low capacitance technology of ansenmey semiconductor into a 3-pin package, protects two high-speed data lines with 0.5 pf capacitance, and provides designers with a single device solution to protect the d+ and d-lines of USB 2.0 ports; Esd11l5.0d can also connect cathode to cathode, and protect a single bidirectional line with 0.25 pf capacitance. It is very suitable for protecting high-frequency radio frequency (RF) antenna lines

Both nup4016 and esd11l5.0d can clamp 15 kV input ESD waveform to less than 8 V in a few nanoseconds, providing the highest level of protection for today's ESD sensitive integrated circuits (ICS). These silicon devices have no wear problem of passive technology, and their reliability and performance will not be affected after many surge events such as ESD

it is worth mentioning that these high-performance silicon protection devices of ansenmey semiconductor not only provide extremely low capacitance and extremely low clamping voltage, but also use extremely small packages. They are excellent protection devices for portable products that need to provide excellent protection performance in ultra-thin packages. For example, nup4016 uses a tiny 1.0 mm x 1.0 mm x 0.4 mm sot-953 package to protect four high-speed data lines. It is the thinnest ESD protection device for high-speed communication interface in the market today

esd11l5.0d adopts ultra small 1.0 mm x 0.6 mm x 0.37 mm sot-1123 package. Compared with similar solutions in the market using sot-723 package, it has a 50% smaller footprint and a 20% lower thickness. It is the thinnest ESD device for high-speed communication, USB 2.0 data and power lines and protection in the market today

ansenmey semiconductor also plans to provide 0201 CSP encapsulated ESD devices with sizes as small as 0.6 mm x 0.3 mm x 0.3 mm to protect a single line, and each line occupies a plane area of only 0.18 mm2

USB 2.0 high-speed application protection example using ansenmey semiconductor protection components

usb 2.0 interface is widely used in portable devices and has a very high frequency of use in users' daily use, so it is necessary to provide reliable ESD protection for high-speed USB interface. Figure 2 shows the concise structure diagram of USB 2.0 high-speed application with speed up to 480 Mbps in the case of lines with identification (ID) and lines without ID

Figure 2: schematic diagram of USB2.0 high-speed (480mbps) application structure

take Figure 2 a) with ID line as an example. In application, three extremely high-speed data lines (d+, d- and ID) and one high-power line (VBUS) need to be protected by devices with capacitance less than 1 PF and small package. For such protection requirements, either discrete protection schemes, such as using three esd9l plus one esd9x, or integrated protection schemes, such as one nup3115up or nup4114up (one line is not connected)

in the application of Figure 2 b), it is necessary to protect two very high-speed data lines and one high-power line (VBUS) with devices with capacitance less than 1 PF and small package. For such protection requirements, it is also possible to adopt discrete protection schemes, such as using 2 esd9l plus 1 esd9x, 1 esd7l plus 1 esd9x or 1 esd11l plus 1 esd9x, or integrated protection schemes, such as 1 nup2114up or 1 nup4114up (protecting 2 USB ports)


, digital cameras and other portable products may be affected by ESD pulses and damage integrated circuits with smaller and more sensitive feature sizes, thereby affecting the reliability of the system. The most effective ESD protection method is to place external protection elements at the connectors or ports of portable devices. The test shows that the clamping performance of silicon TVs diodes is better than that of passive components such as polymers and varistors, while the silicon protective components of ansenmey semiconductor are better than the closest competitive devices. As a leading supplier of high-performance and energy-efficient silicon solutions in the world, ansenmey Semiconductor provides a wide range of high-performance silicon protection components for high-power, high-speed and extremely high-speed applications of portable devices, many of which are leading products in the industry today. These leading products provide extremely low capacitance and extremely low clamping voltage in a very small package, which is very suitable for protecting extremely high-speed applications such as USB 2.0 high-speed and HDMI. At the same time, customers benefit from the rich silicon protection component series of ansenmey semiconductor, and can flexibly select and match the silicon protection components of ansenmey semiconductor for its USB 2.0 high-speed and other applications to meet their different application needs

Copyright © 2011 JIN SHI