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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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21 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 ...
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60 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 ...
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50 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 ...
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37 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 ...
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31 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 ...
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2answers
46 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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56 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 ...
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2answers
277 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 ...
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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 ...
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103 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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71 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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61 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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33 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
127 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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89 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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1answer
90 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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25 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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64 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
65 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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98 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
188 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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77 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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177 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
55 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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49 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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134 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
60 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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356 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
178 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
93 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
387 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
3k 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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428 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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241 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
160 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
919 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
72 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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183 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
252 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
148 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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67 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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223 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
90 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
292 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
72 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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35 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
157 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
74 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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115 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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55 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 ...