旁路電容與氧化鋅變阻器在靜電保護上的效果

Question

旁路電容與氧化鋅變阻器在靜電保護上的效果何者為佳? 爲什麼?
在電容上由於 Xc = 1/ 2πfc,所以當容值越高,對於高頻訊號的吸收會較有幫助
在突波也算是種雜訊,可利用電容特性來濾除

但是在靜電方面? (靜電方面跟突波差異為 靜電更為快速 大概在幾個ns到達peak,突波為µs級)

不知道要找大電容還是小電容的,或是要選擇什麼樣的氧化鋅變阻器中.... QQ

Answer 1

如果是nano second 的ESD,用 Varistor 可以承受較高的電壓,下表是各種保護元件的優缺點.Ceramic CapacitorZener DiodeTransient Suppression DiodeMultilayer VaristorSchottky DiodeBarely withstands high-voltage ESD surgesStrong resistance to surge than ceramic capacitorsStronger resistance to surge than ceramic capacitorsRugged; does not fail even at highest voltaghe levelProtects limited parts of a printed circuit boardSurge energy does not dissipate against heatHigh clamping voltage; heat dissipation is slowLow clamping heatLow dc breakdownLow clamping voltage—Does not protect against nanosecond ESD eventsDoes not protect against nanosecond ESD events—Does not protect against nanosecond ESD eventsCeramic—Available in small packagesCeramic; surface-mount packagingSurface-mount packagingTable I. Basic characteristics of ESD protection devices.