IEEE C62.59:2019 pdf free download – IEEE Standard for Test Methodsand Preferred Values for SiliconPN-Junction Clamping Diodes
7.4.1 Introduction
The measurement of thermal resistance and transient thermal impedance is based on the use of a temperature-sensitive parameter of the semiconductor as an indicator of virtual junction temperature (T).The forwardvoltage (V) of a diode, at a small percentage of rated current, can be used as the temperature-sensitiveparameter or the breakdown voltage(VsR)(see IEEE Std C62.37TM-1996[B18] and JESD282B.01[B33]).
B.3 Clamping voltage
A key parameter is the ratio of clamping voltage to limiting voltage threshold as this represents the levelof overvoltage above the maximum system working voltage. The overvoltage ratio depends on the surgewaveform used. For example, the component 8/20 current rating is about seven times the 10/1000 currentrating.The much higher 8/20 current,in turn，results in a much higher clamping voltage and a higherovervoltage ratio. Figure B.1 shows some curves plotted from manufacturers specifications for the differenttypes of clamping technology and surge waveshapes.
c.1 Introduction
Manufacturers have component quality policies covering materials，products，services，manufacturingprocesses,tests,controls,handling, storage, and transport measures as well as the management to ensurecomponent compliance with the declared specification.This annex discusses the component productionapproval process in terms of characterization and rcliability.
The standards used for qualification tests depend on the component itself and its intended use. The componentmay be supplied in wafer (chip) form, in hermetic packaging, or in non-hermetic (plastic) packaging withthrough-hole leads or in surface mount. This annex concentrates on plastic packaged components, where thepackage slows up the ingress of contaminants that can degrade the chip and its connections. The intendedcomponent usage sets the most appropriate reliability standards such as for automotive the AutomotiveElectronics Council (AEC)Q101 [B1].
c.2 Test samples
Test samples should reflect production variances. Typically, these variances may be created by processingthree separate wafer batch lots, not processed at the same time, and assembling portions of these lots in threeseparate packaging runs. Where a generic component is being qualified, the three production lots should befor the highest voltage component, the lowest voltage component, and a mid-range voltage component. Equalproportions of the different components produced then form sample groups to be tested.A sample group sizefor electrical characterization is typically about 30 components.Reliability testing can use sample sizes up to77 components, whereas mechanical testing might only use 5 components.
C.3 Electrical parameter distribution
The measurement of the component specification electrical characteristics is straightforward as they aremeasured values.Besides taking 25 °C measurements, further measurements may be needed at the componentoperating temperature extremes.
Verifying the surge current ratings is more difficult, as the true surge capability needs to be established andcompared to the specification value. Normally this would be done by a surge step stress test that measuresa sensitive electrical characteristic after every surge，the test culminating when the measured electriccharacteristic exceeds specification limits (see 6.l of IEEE Std C62.42.3-2017).Surge verification mayinvolve several waveshapes such as 2/10,8/20,10/160,5/320,10/560, and 10/1000.