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Questions tagged [esd]

ElectroStatic Discharge, it's caused by accumulation of electrostatic charge as a result of rubbing, and can damage semiconductor devices like integrated circuits.

5
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1answer
600 views

Why is my ESD wriststrap failing with nitrile gloves on?

I have recently ordered some nitrile gloves for the cleanroom of which I am lab manager. I noticed that when I wear the gloves and test the ESD wrist straps, they are all failing. Can someone ...
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vote
2answers
79 views

how to make an ESD sensitive circuit?

I have an experiment where I plug a sensor to an ESD (Electrostatic Discharge) protection circuit. Sensors are very expensive and very sensitive to ESD. I have tested my protection circuit it is ...
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0answers
15 views

Bulk Current Injection on CAN bus

I'm trying to understand how the Bulk current injection would look like on the CANH and CANL lines, to understand the overloading of the ESD protection diode on the CAN lines and capacitors in ...
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1answer
61 views

Grounding of IT equipment for office ESD protection

We've been having a lot of problems in my office with ESD. People touch cubicle frames and monitors shut off momentarily, painful shocks through laptops, etc. I'm worried about equipment getting ...
27
votes
5answers
6k views

Is it a bad idea to plug the other end of ESD strap to wall ground?

I have gone through this answer on Superuser, while it provides good information, I still have a specific question from electrical/electronics engineering point of view. Is it wrong and unsafe to ...
2
votes
1answer
46 views

ESD protection of battery operated device in metal case

I have a board design inside a metal case (video processing MCU), and it has one external USB port with ESD protection on all pins. It's battery powered and handheld. The exterior metal case is not ...
3
votes
1answer
51 views

Adding SMA conectors to a device whose metal casing is connected to earth ground through at a single point

We are iterating a device whose metal chassis is internally connected to an ESD guard ring that is connected to the PCB signal ground through a 0Ohm resistor in a single point close to the power ...
0
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1answer
31 views

ESD diode with zener configuration is equivalent to a circuit containing diode, transistor and zener diode, so how this could be equivalent

please tell me in the following link (https://www.onsemi.com/pub/Collateral/ESD9101-D.PDF), the ESD diode with zener configuration is equivalent to a circuit containing diode, transistor and zener ...
3
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2answers
924 views

Test pad's ESD protection

I design a module with onboard test-pads. I put ESD protections to all out-world connections like sockets etc. But I want to ask that; should I put ESD protections to test-pads and ISP socket inputs?...
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0answers
50 views

TVS diode selection for 3.3 V GPIO

Please refer to my project architecture in the image below: Power supply is isolated flyback smps type. GND is not connected to Earth or Neutral of 220 VAC. All parts of circuit are powered up with ...
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0answers
50 views

Protection against ESD/EFT/Surges

One of my project architectures looks like this: GPIO / 595 output / 12 VDC wire lengths will not exceed 25 cm. I have faced MCU lockup issues due to EFT in the past and want to make sure this ...
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1answer
58 views

Use of internal PCB ground plane as ESD baseplate/EMC reference plane of product in plastic enclosure

I am designing an electronic product which will be housed in a plastic (non-conductive) enclosure. There are a number of, mostly shielded, I/O cables (Copper 10/100/1000Mb/s Ethernet, USB 2.0, RS232, ...
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1answer
43 views

Soldering Iron and Electrostatic Bracelet Connection

I have a DIY soldering station and I want to ground the soldering iron and I also want to use a electrostatic bracelet connector for the soldering station. Can you please help me how to connect the ...
1
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1answer
78 views

ESD protection using capacitor

Will a capacitor actually help to lessen the effects of ESD? Because, with rise time of about 1 ns, the frequency of the ESD signal will be well above the self-resonance frequency of the capacitor and ...
0
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0answers
75 views

USB fail to pass ESD test even with TVS diode protection

I have read some articles about USB ESD protection and followed the suggestion to add TVS Diode Array USB6B1 in my design. However, my design is still failed to pass the ESD test and I don't know ...
2
votes
1answer
56 views

ESD Grounding Straps with No Chassis Ground

I've got water pump device that needs to pass ESD testing (IEC 61000-4-2, 8kV contact, 15kV air discharge). On this device (as circled in red), there are these four metal inlets. At 2kV with an ...
1
vote
1answer
63 views

DC floating ground and TVS Diodes for ESD

I want to provide ESD protection for a low voltage battery powered device and I do not understand what sort of net I should attach to the cathode side of the TVS diodes: I do not have a strong ...
1
vote
2answers
55 views

Preventing under-voltage from ESD strike to ground in floating circuit?

Consider a circuit like this... simulate this circuit – Schematic created using CircuitLab What happens to the voltage seen by the MCU between VCC and GND when this circuit takes a positive ...
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2answers
67 views

Protecting analog pin from ESD strike

After reading some relevant questions on ESD here, I have come up with the following approach to protect some ADC GPIO pins on my lipo battery operated board that are open to external input, thus ...
5
votes
2answers
282 views

Any tricks for finding the path taken by small ESD sparks across a PCB?

A small ESD spark is able to find its way across my PCB at a relatively low voltage (low kV). It is not obvious which path the spark is taking and the sparks only jump when the board is sealed up ...
0
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0answers
68 views

Should I touch the metal surface of my ESD wristband?

Most ESD wristbands have a little metal surface (something like 20mm*15mm) and a part of plastic or some sort of cloth that goes around the arm. Is it enough to touch the non-metal part or should I ...
0
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2answers
217 views

The role of the series resistors for ESD protection

When one needs to protect a transistor or I/O pin of a processor, then a TVS diode can be placed between the connector and the transistor. Also a series resistor (R1) can be placed between the ...
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2answers
94 views

ESD problem on water tank?

We have a water level monitor attached to a water tank. The water monitor has an hydro-static (output 0-5V) water sensor that goes to the bottom of the the tank. (See figure) In most cases this works ...
0
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1answer
103 views

ESD protection for battery powered device

I have module that will be plugged into another device. The unit itself has no power and receives all power, and signaling from the mating devices. It has a 10 pos exposed connector (male pins) to the ...
0
votes
1answer
42 views

Connection of LAN8742A nRST pin causes failure when ESD strike

My circuit uses LAN8742A ethernet phy. The system has a metal case and gets 220V AC to power supply board. After converting 5V DC it goes to my board that has Ethernet and mcu. I screwed case and ...
0
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2answers
220 views

Protecting USB hub from ESD

I am working with a robot that uses USB (not by choice lol) in a very static-prone environment, and I'm having problems with ESD locking up my USB hub. I found an "Industrial" USB hub that claims it ...
1
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1answer
131 views

ESD strike breaks the LAN8742A ethernet phy

My circuit uses LAN8742A ethernet phy. The system has a metal case and gets 220V AC to power supply board. After converting 5V DC it goes to my board that has Ethernet and mcu. I screwed case and ...
1
vote
1answer
132 views

Connection of ESD return path the System GND

In my current design I have one RJ45, one RS232 and two RS485 ports. I have TVS diodes CDSOT23-SM712 for serial channels and ESD7104MUTAG for Ethernet port. Now I have connected the ESD GND of the TVS ...
1
vote
1answer
28 views

ESD/overvoltage protection with DM1231-02SO TVS array

I'm protecting a USB2.0 IC against ESD and overvoltage at the USB connector using a Diodes Incorporated DM1231-02SO TVS (dual) array. The datasheet labels the pins IN and OUT, but it's not 100% clear ...
1
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2answers
108 views

ESD diode selection based on VCC of the IC

I have a question about TVS diode selection. This kind of question is already discussed in previous questions. ESD Diode - GPIO Microcontroller Selecting a TVS for ESD protection For protecting vcc ...
2
votes
1answer
70 views

Logic Level Translator with series resistors

I'm designing two MCU boards. These boards will be used for somewhat different purposes, but they should communicate with each other via UART. One of the MCUs has an I/O voltage of 5V, while the other ...
1
vote
0answers
162 views

power surge protection

I've seen power protection that uses: MOV (metal-oxide varistor) Inductor TVS diode Application Note: Transient Voltage Suppressors (TVS Diode) Applications Overview I didn't see any design ...
0
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2answers
325 views

Unidirectional vs Bidirectional TVS on USB devices

Is there a reason to use unidirectional TVS diodes over bidirectional TVS on USB circuit protection apart from cheaper cost? As USB is a DC powered circuit, I feel like unidirectional TVS diode (such ...
0
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1answer
79 views

Increased current consumption of micro-power devices

I've been working with microwatt and nanowatt power consumption devices for a while and I've mentioned that sometimes, due to unknown reason, current consumption increases in order of magnitude. ...
2
votes
1answer
227 views

Is the ESD and overvoltage protection for my ADC circuit sufficient?

I am currently building a data logging device for monitoring battery packs which contain 8 Lithium cells. The device will periodically log the voltages of all 8 cells, as well as log temperatures ...
1
vote
1answer
60 views

Lightning protection for Antenna Connector

I want to add lightning and ESD protection for the antenna used with my PCB (Wireless Gateway). The antennas that will be used with my PCB are Pole Mount Antenna. There are three different types of ...
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0answers
56 views

Voltage Rectifier Fails When Doorbell Button Shorts Inputs [duplicate]

I am working on a project that involves powering a 3.3V microcontroller off a doorbell transformer. The design uses a full-wave bridge rectifier (1) to convert the AC voltage from the doorbell ...
0
votes
1answer
216 views

ESD capacitor simulation for human body model

I have designed an ESD suppression circuit with the help of ESD capacitor using LTspice. In the circuit, 15kV input pulse is given to ESD human body model and the resistor, capacitor used near the ...
1
vote
1answer
106 views

Can I use a simple resistor for ESD protection on an ESP32?

This question applies both to digital and analog inputs on the various ESP32 dev kits. From what I can tell, none of these boards (including my OLIMEX-EVB and Gateway boards) add any ESD protection ...
3
votes
3answers
359 views

Should I wear a grounded ESD strap when probing/debugging my raw boards?

Manufacturing and handling the unpowered boards, the assembly workers often use strict ESD control: dissipative mats, smocks, and grounded wrist bands. As an embedded engineer, I am always powering ...
2
votes
4answers
239 views

Enhancing TVS diode circuit

I was reading into Electromagnetic Compatibility Engineering by Henry W. Ott about ESD protections and I was interested by the following part. First, a series resistor (or ferrite) added in front ...
2
votes
4answers
104 views

Flooring for home lab

I am setting up a home electronics lab for projects with my kids, currently ages 4 through 10. What type of flooring would work best? We will be doing art projects in the same room, so we need ...
4
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3answers
434 views

ESD ratings of diodes and bipolar transistors

While it's easy to find ESD ratings for ICs (bipolar, CMOS, and any mix) and to some extent for MOS transistors (for the inherent reasons), I don't find ESD rating for many common diodes (left apart ...
20
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4answers
4k views

USB Shield. To ground or not to ground?

I have been given a device at work to do some testing on. Basically an IC is becoming obsolete so I need to test a replacement part. Upon redoing the ESD checks, the device failed. I checked the ...
4
votes
1answer
437 views

Grounding the table

I'm preparing my private laboratory stand. I want to use an ESD mat, but my power outlet is far from the table so I can't ground it directly. I want to ground the mat on a table and I wish to use an ...
1
vote
1answer
336 views

evaluating ESD protection for 3.3V i2c

Even though there are questions about ESD protection for i2c bus already in this forum, I wanted to ask how to suppress the clamping voltage of a TVS diode to a safe level. As an example, the ...
2
votes
1answer
204 views

reducing the voltage clamped by a TVS diode for SPI bus

I'm making a board with an AVR. Between the MCU and the connector I would have multiple lines for SPI communication. Since the environment of this board is expected to be very dry, it is needed to ...
5
votes
3answers
1k views

ESD protection on analog signals

I have a board which has its microcontroller pins directly breaking out to a breakout header. I am fairly certain the board won't be in ESD safe environment when being tested. I decided to get ...
1
vote
0answers
86 views

TVS protection burnt too easily

It's about an year that I'm using TVS diodes to suppress spikes from the AC motors (240V - max 240W) that drives my roller shutters and protect the solid state relay that actuate the motor. What is ...
4
votes
1answer
296 views

ESD from plastic enclosure to PCB in floating systems

I'm designing a battery powered device. The device will be placed in an environment where the relative humidity is below 20%. So it is essential to protect the electronics from potential ESD events. ...