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.

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39 views

Fix burnt USB port [closed]

I accidentally connected the 5V output of my arduino UNO with a 12V power adapter (I wanted to use a transistor as a switch for turning on some fans and touched the breadboard line). Unfortunately, ...
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21 views

Voltages and charges with regard to ESD

My question is with reference to this question - ESD protection using a capacitor I am unable to grasp the relation between charge, voltage, and capacitance, although I can understand all these terms ...
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71 views

Is it Possible to Static Test With a Barbecue Lighter?

I'm working on an issue with a product where it freezes due to static shocks. I'm trying to recreate the issue and harden the product, but I don't have a real static testing wand like the test labs ...
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2answers
67 views

Are small signal relays vulnerable to ESD?

I am looking for a small relay to help me with network cables. The system needs to be able to withstand a reasonable electrostatic discharge on the cables. I am using MAX485 network chip, which has ...
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1answer
52 views

Protection against electrostatic paint by draining the charge

I have a circuit for an automotive sensor aimed for 24V supply. The circuit itself is well tested for EMC requirements including power line transients and EMC immunity. Usually the requirement is for ...
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88 views

Are ESD safe tools necessary with proper setup?

My current setup is an ESD mat and ESD wristband both connected via alligator clips to unpainted screws that are screwed into a secondary PC power supply (not mounted in a PC case.) This power supply ...
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57 views

Can you deal esd damage to an internal PCIe solid state drive while it is inside an anti-static bag?

I apologize for the paranoia, but my mind refuses to rest. I have recently been working on a laptop. While doing so, my SSD (internal, it's a PCIe board) was inside an anti-static bag (the very cheap ...
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1answer
56 views

Issues with this USB ESD protection circuit?

I've used this ESD circuit on four boards for hobby projects. I have had no issues on two boards. On two others, the TVS diode for VBUS conducted when the board was plugged into a USB port, causing ...
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1answer
252 views

Metal enclosure grounding for audio project

Fellow engineers, For various reasons I picked extruded aluminium enclosure for my current audio related project. All exposed metal connector chassis are connected to earth, which then goes to ground ...
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111 views

Are paperclips conductive enough for anti-static purposes? [closed]

I have recently discovered that I am a very silly man. Despite this, for the purposes of laptop repair, I still want to ground myself without spending any more money. I have recently come in to the ...
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4answers
121 views

Can I safely ground myself by clipping an anti-static wristband to a half-inserted plug?

I'm having some trouble grounding myself for laptop repair. I cannot get the crocodile clip of my anti-static wristband in to my plug socket (I'm in the UK, so our sockets are a bit difficult) and I ...
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Is plugging a wrist strap in enough to prevent ESD?

I've been told by a few people that if you plug in a PC and switch off its power supply that it is enough to prevent ESD. But I was taught differently. I was taught that it's more about difference in ...
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Do li-po batteries need esd protection?

I bought some li-po batteries and they were in antistatic bags. They have protection circuits. Do they need esd protection (grey bags)?
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2answers
82 views

Can ESD damage a board that is not powered up?

I have a PCB in the field that is put in an enclosure box and is placed on a pole in an open environment. My question is, if the PCB does not have the power supply connected, can ESD still damage the ...
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1answer
209 views

Increasing ESD protection on Isolator part of the board

How it is possible to increase ESD protection of isolator ISOW7842DWER to tolerate 8KV ESD spike?
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3answers
167 views

circuit for hot-pluggable device

I have a scenario, where device A provides 24V, device B converts 24V to 3.3V and feeds it back to ...
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27 views

Selection of current limiting resistors to limit the current of ESD UART / I2C buses

Since the connection to the I2C and UART buses goes through connectors, where there is a possibility of ESD formation, I would like to limit their current. As the protected device there will be a ...
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42 views

Voltage spikes caused by stray wire

I recently had a PCB designed which has several analog, digital, and power elements. The board is powered by 24Vdc which is stepped down using an LDO to 3.3V and 5V. These voltages are used to power ...
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31 views

TVS ESD diode power rating

Is there any rule on how to choose the power rating of a bi-directional TVS diode which will be used in automotive 12V system as an ESD protection? They range from 20-40W all the way to 1000W and ...
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21 views

How do I model CDM in Hspice

I am trying to model CDM (250V)so that I can check my RC clamp circuit using Hspice . If you have any model please share .
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3answers
515 views

Why use a PMOS transistor instead of a diode for ESD protection?

I am working on updating a PCB design by adding ESD protection to the power supply. I see that an experienced engineer at my company has placed a PMOS transistor rather than a series diode, and I'm ...
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741 views

Are MOSFET drains ESD sensitive?

There's a lot of post on here about MOSFETs and ESD sensitivity. But whenever the general question is asked, people always go straight to the gate and how sensitive it is. I've developed an LED ...
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8answers
3k views

How to inflict ESD damage on a board?

I have a mature product (designed by me) on a PCB. For science, I would like to induce Electrostatic Discharge (ESD) damage to the board so I can see how it behaves afterwards. This test would be ...
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1answer
128 views

ESD SPI/ISP bus protection

I am designing a board based on the Atmega328P microcontroller. For this controller there is an ISP connector for programming. This connector has the following pins: MOSI / MISO / RST / SCK. There is ...
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1answer
67 views

Component case size and spacing for ESD protection circuit

As im searching for TVS diodes, I see a 30KV rated diode array has pins RIGHT next to each other. Aren't they so close that a spark can easily jump between pins?? I read a few time that you need a ...
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37 views

ESD Input protection on low Vmax digital inputs (3.6v)

I have a microcontroller monitoring a few digital inputs. The max voltage on these inputs is VCC + 0.3v. VCC is 3.6v so these inputs can't be higher than 3.9v. These digital input are just switch ...
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162 views

How to protect input against both ESD and reverse polarity?

I need to protect an external input on a device against both reverse polarity and ESD (IEC61000-4-2 +-8kV). The normal input is +5V dc at 100-200mA; the reversed input could be -5V and that should be ...
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106 views

Should I connect the computer VBUS line to the 5V line of the board?

I am doing a project that needs USB communication with my microcontroller. On the board there is already a 5V power supply. I would like to know if it is correct to ...
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1answer
218 views

Unidirectional vs Bidirectional TVS diode for ESD protection UART bus

On my board comes a UART line with a voltage of 3.3V. To safely communicate with the controller on 5V, I use a level offset based on BSS138 transistors. My goal is reliable ESD protection of the UART ...
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2answers
116 views

When should ESD Protection Diodes be used?

I'm working on a heated glove project that uses a Buck-Boost converter to step-up/step-down the voltage across the heating element. This is something that has just occurred to me, but I'm not sure if ...
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3answers
86 views

Confusion about TVS-wiring with RS-485

I'm currently looking into securing my RS-485 connections against ESD. My current understanding is that a TVS diode is put between the data line and GND, so that any discharge will be shorted to ...
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1answer
210 views

I keep zapping mosfet and I don't know why

After asking collagues, trying a few variations and spending days on research, I figured out I could ask there as I am running out of ideas. The most similar discussion I have found is: mosfet is ...
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1answer
72 views

The Thermal relief consideration for TVS diode (for ESD protection)

I am designing a print which has some mircofit connectors, I have placed TVS very close to the connectors on the print and the ground pad connected with a GND polygon directly, this polyon connects ...
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48 views

Can any of the below damage a SIM800L module?

I was developing a simple circuit using an Arduino pro mini and a SIM800L when I understood that SIM800L's Vcc and Gnd pins have been shorted. I tested short circuit using the continuity and resistor ...
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1answer
356 views

Placement and values for ferrite bead/capacitor ESD protection / transient suppression filter

I've been researching but found it difficult to find a clear answer on this. I need to add ESD protection to my circuit, in this Texas Instruments video it talks about combining a TVS diode with a FBC ...
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1answer
74 views

Should isolated GND be tied to logic GND to prevent ground drift?

In an industrial environment, let's say you have an isolated interface that connects to an external sensor or device. This interface separates both logic signals to your main board as well as GND and ...
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2answers
83 views

How to connect the GND with the metal case of the robot

I have a PCB design inside a metal case of the robot. The robot is mobile, it moves on wheels. The problem is how to connect the GND with the metal case of the robot. Direct connection is not safe, ...
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1answer
116 views

ESD protection diodes on audio inputs / outputs?

I'm building a digital audio device with 1/4" stereo in and outputs that connect to a CS4272 codec. I'm wondering if and where I should place esd protection diodes. Pictured below is the analog part ...
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57 views

How to harden/prevent ESD in a circuit?

I've designed a simple circuit with three LEDs in series with a matching resistor, all powered by an IC. I want to make my circuit less susceptible to electrostatic discharge since it will be ...
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2answers
85 views

What is the purpose of R1, R2 in this ESD protection circuit

What is the purpose of R1 and R2 in this circuit? Is it required? I have seen in documents like https://www.onsemi.com/pub/Collateral/AND8169-D.PDF where no resistors are shown in the example ...
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1answer
80 views

ESD Mats failing with constant monitoring system

Good afternoon, This is my first time posting here, and I apologize if I am doing anything incorrectly. I'm already a member on StackExchange so I thought I would stick to this website for this ...
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2answers
183 views

What is the purpose of this 5 V protection circuit?

I'm working in the OEM company and I want to know what the purpose of the below circuit is. Whether +VCC5V0 or -VCC5V0, Q8 is off so I don't know the purpose of this circuit. It should be a ...
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90 views

transient protection for 0.5W laser diode switching driver

I'm some way into a project which involves switching 0.5W laser diodes at 100kHz, with a pulse of around 1us in width. I'm having issues with the diodes (which I don't have a datasheet for) failing ...
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1answer
44 views

Location for placing ESD components for UHD video

I am implementing ESD protection for HDMI video input. The HDMI video goes through a custom cable of ours, into a connector board attached to our enclosure, through an edge card connector, into our ...
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103 views

ESD Diode - clamping voltage

I'm trying to replace an existing ESD diode(PESD1CAN) in my application CAN circuitry due to some reasons, I've found an alternative ESD diode(RSB27C2), but compared to the diode that I already have ...
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11answers
5k views

How to safely discharge oneself

At work I have the problem that I seem to collect a lot of static charge as soon as I leave my desk and return. I am not quite sure why this happens. Strangely enough the effect is stronger the ...
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911 views

Some questions about antistatic wrist strap

The photo below shows an antistatic wrist strap grounded to the chassis of a PC through its alligator clip: I have three basic questions: If the chassis above is not earth grounded, does it make no ...
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1answer
217 views

Overloading of ESD protection diode on CAN lines through current during Bulk current injection - test

I have a design checklist question for a typical CAN circuit for an automotive application as below : The question is related to the ESD suppressor : "Was a capacitor parallel to the diode considered, ...
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1answer
98 views

Placement of RC filter used for slew rate limiting (for EMC)

I've seen RC combinations used on many circuits now which i believe have been included for slew rate limiting. They usually feed off to a connector. Do the placement of these matter in the circuit? ...
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1answer
222 views

How do anti-static wrist strap alarms detect a disconnection of the wrist wrap?

Sometimes I need to disconnect my ESD wrist strap, but forget to reconnect it again. Apart from improving my discipline to work more structured and more carefully, I wondered if there was any device/...

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