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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.

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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 ...
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1answer
42 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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40 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 ...
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46 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 ...
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1answer
25 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 ...
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2answers
87 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 ...
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68 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 ...
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18 views

How to prevent ESD in a capacitive sensing system?

A friend of mine has built an interactive installation on a wall using a Bare Conductive microcontroller board (arduino based, 5v) which is connected to a PC. The interface is made of conductive paint....
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58 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 ...
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1answer
20 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 ...
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39 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 ...
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1answer
60 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 ...
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61 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 ...
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2answers
101 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 ...
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1answer
73 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. ...
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1answer
117 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 ...
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1answer
43 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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43 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 ...
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1answer
70 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 ...
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1answer
51 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 ...
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3answers
351 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 ...
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4answers
116 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 ...
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4answers
82 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 ...
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3answers
360 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 ...
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4answers
2k 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 ...
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1answer
421 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 ...
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1answer
153 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 ...
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1answer
106 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 ...
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3answers
815 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 ...
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0answers
66 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 ...
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1answer
119 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. ...
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2answers
151 views

ESD protection for power lines using capacitors

I heard that a capacitor can protect a DC power line from a transient voltages by ESD event. Unfortunately I don't understand how it works in detail. It would be appreciated if someone could answer ...
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2answers
116 views

ESD/EMI Design for CE, Recommendation seems wrong from test lab

I have designed a product for a customer, that now needs to pass UL/FCC/CE Testing, It passed UL & FCC but failed CE for both 8kv ESD and EMI. The Chinese test lab my client went through sent me ...
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53 views

how can I get leakage current in tlp?

I got tlp test data and found that the current at vertical line means leakage current. But I don't understand the method how does the tlp-test measure the leakage current. I tried to search the ...
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154 views

when do you expect negative ESD?

If you have an I/O pin to protect, don't you always need the protection from both positive and negative ESD? I see that many circuits have clamping diodes connected between I/O nodes and power nodes. ...
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1answer
73 views

ESD potection in the PCB

I am using micro USB socket to charge the battery in one of the device and now we are planning to go for CE certification for which we are doing EMI/EMC test. For the ESD IEC 61000-4-2 (+/- 6 kV ...
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1answer
197 views

TVS diode array for 3.3V I2C lines

I want to protect sensors that use 3.3V I2C from strong ESD. After searching internet for a while I found that LCO3-3.3 provides protection from 30kV. However, I'm still not sure if the one can be ...
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1answer
66 views

The possibility of ESD in an isolated, mobile system

When you have an isolated, battery powered device, then shouldn't you expect ESD? Let's say I have two boards connected with each other through cables and connectors. The components on the PCBs are ...
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29 views

Varistor clamping voltage calculation

I would like to know if it is possible to calculate the clamping voltage provided by a varistor to an IC pin for an automotive ESD waveform ISO-10605 8kV. I would like to know if it will protect my ...
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1answer
122 views

Ethernet PHY TX & RX pin failures

I am seeing a problem with Micrel Ethernet PHY KSZ8721BLI. Because of some mechanical constraints, the PHY is located near the edge of the main board and a small card edge connector. The board slides ...
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1answer
70 views

What are these fuse-looking cartridge case components on small, battery operated RF tranceivers?

I have recently opened up 3 dead, battery-operated RF transceivers lying around, both wearable and key-chains. I've noticed that all three had components that looked like fuses (cartridge case), ...
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1answer
113 views

Question about ESD wristband and lightning

as far as I know all ESD wristband's ground connection has an 1M ohm resistor built in for safety. So what would happen if I am working on lab wearing ESD wristband which is connected to the home ...
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1answer
47 views

microUSB casing to the ground, ESD protection

I am thinking to use TVS diode TPD1E10B09 for ESD surge protection. The general convention is outer edge of the microUSB is connected to the ground, so any ESD strike happens it will be grounded. But ...
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1answer
196 views

What is a ESD tube?

In the ESP32 datasheet, what do they refer to with "ESD tube"?
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1answer
65 views

Shipping & Handling Electronics & Electro-mechanical parts

What are common packaging(Shipping & Handling) guidelines (specs/stds) for Electronics & Electro-mechanical parts? Currently, working on adding onto our current generic guidelines for ...
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2answers
494 views

Decoupling capacitors on I2C interface + ESD protection

I had one of my PCB designs reviewed by someone and the reviewer suggested that I add decoupling capacitors on the clock and data lines of I2C interface. I am a bit surprised as I have always seen ...
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2answers
190 views

Protecting microcontroller digital output pin from ESD, reverse connection, and other possible user error

I want to protect an output pin from ESD, reverse connection, and other possible user error that might cause damages to my circuit. This pin output pulses depend on the amount of water passing through ...
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5answers
324 views

How necessary is ESD protection, really?

I'm not asking about manufacturing. I'm asking about designing electronics to survive normal use in the field. I want to figure out just how necessary it is to include TVS diodes in my design. As I ...
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1answer
74 views

MOV max clamp voltage

Here in an interesting discussion about MOV specifications If I want to protect a 3.3V circuit tolerant to 5V voltage against ESD, I can select a little fuse MOV for example V3.5MLA0603. I want to ...
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70 views

Is there any sense in carrying assembled enclosed electronics in a static-shielding bag?

Say I have a Raspberry Pi enclosed in a metal case, such as this: Would it offer any additional level protection if I put it in a static-shielding antistatic bag whenever I carry it around (e.g. ...