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14

Does this answer your question (emphasis added)? 9.3.2 Test method The test method shall be in accordance with EN 61000-4-2 [2]. For radio equipment and ancillary equipment the following requirements and evaluation of test results shall apply. The test severity level for contact discharge shall be 4 kV and for air discharge 8 kV. All other details, ...


8

Not all ESD protections are using this "classic" circuit: simulate this circuit – Schematic created using CircuitLab In more modern designs, some diodes might be replaced by "grounded gate NMOS" where the parasitic "snap back" behavior of the NMOS is used as a fast clamping device. simulate this circuit When you measure ...


8

A TVS diode is typically capable of much higher power than ESD diodes. TVS - "Transient Voltage Suppression" can, if rated accordingly, be capable of suppressing surge pulses - these are pulses that have several hundred volts (and a generator capable of sourcing several hundred of amperes) for a few microseconds. A few microseconds might not sound ...


7

It is very easy to damage a circuit with ESD WITHOUT EVER DISCHARGING ANYTHING. A simple experiment demonstrates this. Wash your hair and let it dry. Blow up a balloon. Rub the balloon against some fur (or your own hair, but the purpose is to show that you can transfer static charges without touching the thing that holds static. Once you have charged the ...


6

You are right that the Raspberry Pi carries a CE conformity. Either they write in the manual of the Raspberry Pi that the user MUST use some kind of housing or they declare the product as an experimental board (or toy) that does not need to pass ESD tests and that the usage purpose of this product is very limited. As you stated correctly: It is hard (if not ...


6

Can a ggNMOS be created discretely on a PCB? I don't think it can. I'm assuming that by "created discretely on a PCB" you mean, using a discrete N-channel MOSFET. The N-channel MOSFETs that are used as ESD protection devices on an IC are always planar MOSFETs. Planar devices are "surface" devices, they work in the horizontal direction, ...


5

Your D1 and D2 are slow diodes and will not react sufficiently fast for ESD speeds. You need TVS diodes for that. But honestly, you probably don't need to take any special measures with such a ridiculously high series resistance, the system parasitic capacitance can probably absorb it/ You could add a small parallel capacitance to absorb it better if you ...


5

The forward current for the diodes in the opto is +/- 60 mA maximum. The series impedance is 4x 27 kΩ = 108 kΩ. With half the maximum rated current flowing from a threatening surge, the voltage across 108 kΩ is 3,240 volts. This is a scene setter. For ESD, the event will be over so quickly that I doubt there would be any problem but, with an indirect ...


5

Antennas are usually connected to Spectrum Analyzers. Looking at the RF signal in the time domain may not provide much information about the signal, like signal distortion. Distortion of a signal can be a very slight change in the wave shape which is hard to see without a reference waveform for comparison (good luck lining those up), whereas on a spectrum ...


5

Is it enough to choose a capacitor that can withstand the final voltage? It absolutely is but, I think where you might be getting confused is the definition of the "final voltage". It's not the 8 kV initial voltage that the ESD generator can produce into an open circuit; it's the voltage that appears across the capacitor (much much less than 8 kV) ...


4

If you can discern the static charge, it's too much to be safe for chips. If you're buying chips from a reputable source they're already coming to you in anti-static bags -- just leave them in. Any passive, non-semiconductor component (i.e. caps, coils & resistors) should be fine with a bit of static electricity.


4

Yes, very definitely. It is insidious b/c the damage by ESD may not always cause outright failure of the component or system. It may result in degraded performance.


4

Sometimes you can feel the electrostatic discharge from your body to the circuit/component but this might not always be an indication of damage. Or, you can't even feel anything but can't understand that the circuit/component is damaged until you powered it. An interesting experience I had: A few years ago, I had designed an LCD monitor control board for a ...


4

Looking at a couple other bidirectional/asymmetrical TVS from Nexperia, Vishay, and ST, the stripe indicates pin 1. I'd test to double check, but it looks like a pretty safe bet that your device is similar.


4

No, they are not. Any plastic like that has the potential to build up charge over time from small movements or vibration (triboelectric charging). I would not use any untreated plastic anywhere near a sensor like that - in the mounting solution or the enclosure. If you require electrical isolation, you should consider something like a dissipative mica ...


4

The oscilloscope should be grounded through its power cord. It will normally have a three pin plug - hot, neutral, safety ground. It should not be capable of being statically charged. The antenna ground is connected to the oscilloscope ground and from there to the safety ground of the house. The antenna should not be capable of retaining a charge. You, on ...


3

There are many types of catastrophic failure mechanisms. Fusing a sub-micron sized gold wirebond or damaging a tiny fast ESD diode that is current-limited with 2 stages can happen in xxx milliseconds with excessive energy. Normally the dissipation of a standard test with a 4kV 100 pF HBM finger model pulse is slowed down with 10k R current limiting and ...


3

If the 10mA rating is 'absolute maximum' you not only should not exceed it, you should not even get close to it. ESD rating is generally for the chip not powered. If it is powered when the ESD strike happens, then other damage can occur. There are other failure modes than thermal, and continuous current that the chip is not designed for can have deleterious ...


3

You cannot measure whether something is able to leak away ESD charge with a multimeter. The resistances required for something to be static dissipative are just too high for a normal meter. You need large electrodes and high test voltages. Also "ESD-safe" has varying degrees: Dissipative: slowly leaks away charge which eliminates charge build-up ...


3

I did some testing with a few materials and an ESD gun, shown here is for conductive foam. (I also did conductive plastic, not shown) The spark would find the nearest "conductive material". An interesting result was if a conductive aluminum plate was placed next conductive plastic, the spark actually preferred the plastic (the were almost ...


3

How ESD damage works: Depending on surroundings the capacitance of a human body is like 100-500pF It is pretty easy to build a 5 .. 50kV potential difference between your body and ground or other object and then see a shiny spark 1..3cm or more when approaching a grounded object. It may as well be somewhat painful. On the other hand, if your very own voltage ...


3

By convention, pin 1 would be marked with the bar. This is supported by the bar being on the left on one drawing, and pin 1 being on the left on the other. It's not a guarantee, though; if you have the chance, you could verify it by applying a voltage (~36V) through a series resistor (~27 ohms) and measuring it each way.


3

I do not see an issue with nylon screws (or plastic in general) if you create explicit grounding path that you control. The choice of mounting hardware depends on many aspects such as EMI requirements as well as grounding path from external(?) ESD sources. I assume you may have a specific reasons to use nylon hardware. If not I would stay with SST. Then you ...


3

I've had trouble where the soldermask opening on the corner of the pad would be a little bit too wide so when soldering components it would short to the trace. This isn't detected by board electrical testing since the short happens when soldering. If you trust the manufacturer to be able to manufacture according to their tolerances, and if the tolerances ...


3

The capacitors will need to have a voltage rating that is higher than the highest DC voltage that will ever be across that capacitor during normal operation. The idea of proper ESD protection using capacitors is that the voltage will never become very high in the first place. The capacitors are supposed to absorb the charge from injected by the ESD event. If ...


2

Many materials can generate electricity from friction, known as the triboelectric effect. If you have some way to increase the humidity in the room, use it. Electrostatic charge forms much easier in dry environments, and it's winter in a lot of the world, which means lower humidity and increased risk of ESD. Lay out all the pieces (still in their anti-static ...


2

here's the general pattern. Ideally, AC-couple the ground plane to FE or chassis. Also think through the consequences of how this interacts with all the non-power signal connections, and every conceivable way of the field wiring being done wrong (often multiple mistakes at once due to wires being swapped or shifted). A common mode choke may be called for too,...


2

Air holes will be problematic being the lowest capacitance and thus highest conductance to transient voltage breakdown. A Mylar shield that still permits air flow would be best to any exposed conductors. I recall tiny gaps around LED indicators on recessed 5mm LEDs with 10 mm high lens on early 80’s keyboards would often fail ESD tests with a Schaefer ESD ...


2

You also need to add initial conditions for L1 and L2: .IC V(C1)=ESD_Voltage V(C2)=ESD_Voltage I(L1)=0 I(L2)=0 .param ESD_Voltage=4k (or what ever voltage you want to test)


2

The ATX power supply earth pin you have circled is directly connected to the metal chassis of the power supply, which in turn is also directly connected to PC metal chassis. So yes, connecting the clip to that pin is completely electrically equivalent of connecting the clip to unpainted PC chassis. There may be other downsides though, it may not stay clipped ...


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