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memsgg
Joined: 01 Aug 2005
Posts: 34
Helped: 1
Location: cambridge, UK
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 13 Apr 2007 16:21 Is ESD protection essential? |
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I just wonder if we must include ESD protection on every pad?
In the low noise and low leakage current application, the input pad should be away from ESD protection, is it right? But is it safe from ESD?
Does anyone know if the commercial opamp input has ESD protection?
Many thanks
Yong
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leohart
Joined: 10 Nov 2006
Posts: 229
Helped: 12
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| 13 Apr 2007 16:39 Is ESD protection essential? |
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I have the same question...will esd bring some noise or distort to the input/output signal?
I would like to use a pin output current about nA-pA(with about 3-5V voltage),is it ok? Will esd itself bring leakage at some pAs when biased at 3V?
Anyone familiar with esd?PLS!
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memsgg
Joined: 01 Aug 2005
Posts: 34
Helped: 1
Location: cambridge, UK
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| 13 Apr 2007 16:46 Re: Is ESD protection essential? |
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| leohart wrote: |
I have the same question...will esd bring some noise or distort to the input/output signal?
I would like to use a pin output current about nA-pA(with about 3-5V voltage),is it ok? Will esd itself bring leakage at some pAs when biased at 3V?
Anyone familiar with esd?PLS! |
I think the ESD leakage is in the range of pA, but not sure...
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leohart
Joined: 10 Nov 2006
Posts: 229
Helped: 12
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| 13 Apr 2007 17:23 Re: Is ESD protection essential? |
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| memsgg wrote: |
| leohart wrote: |
I have the same question...will esd bring some noise or distort to the input/output signal?
I would like to use a pin output current about nA-pA(with about 3-5V voltage),is it ok? Will esd itself bring leakage at some pAs when biased at 3V?
Anyone familiar with esd?PLS! |
I think the ESD leakage is in the range of pA, but not sure... |
My usage is to layout some test big photodiodes and test their dark current, the dark current is as tiny as pAs...If esd bring pA leakage, I have to give it up.
The only concern is if it is safe to remove the esd protection, will the chip be so fragile to electrostatic...I don't want burn my first tapeout just when I touch it...
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srieda
Joined: 24 Dec 2006
Posts: 163
Helped: 17
Location: India
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| 14 Apr 2007 10:28 Re: Is ESD protection essential? |
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Electrostatic generation can occur due to friction between different materials, which is called a triboelectric charging and the potential induced by charges depends on the triboelectric property of materials. Therefore, people as well as equipment are able to easily generate ESD events during all stages of device manufacturing. For instance, the simple act of walking across a vinyl floor can generate up to 12000 V of static electricity depending on the relative humidity (RH). The accumulated charge due to ESD is discharged in typically 0.2 to 200 ns when the object contacts an effectively grounded object. ESD is an extremely fast event, and occurs from various sources, including human beings, machines, electromagnetic, nuclear and other harsh
environments.
A survey showed that 40% of IC failures are actually due to ESD/EOS related issues...
Hence ESD protection is a must for all chips...
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leohart
Joined: 10 Nov 2006
Posts: 229
Helped: 12
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| 14 Apr 2007 10:57 Re: Is ESD protection essential? |
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| srieda wrote: |
Electrostatic generation can occur due to friction between different materials, which is called a triboelectric charging and the potential induced by charges depends on the triboelectric property of materials. Therefore, people as well as equipment are able to easily generate ESD events during all stages of device manufacturing. For instance, the simple act of walking across a vinyl floor can generate up to 12000 V of static electricity depending on the relative humidity (RH). The accumulated charge due to ESD is discharged in typically 0.2 to 200 ns when the object contacts an effectively grounded object. ESD is an extremely fast event, and occurs from various sources, including human beings, machines, electromagnetic, nuclear and other harsh
environments.
A survey showed that 40% of IC failures are actually due to ESD/EOS related issues...
Hence ESD protection is a must for all chips... |
You mean mass proudctive chip,but for test,is esd a must?I know some tests don't use esd,but I dont know much about it,any suggestions or precautions?
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srieda
Joined: 24 Dec 2006
Posts: 163
Helped: 17
Location: India
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| 15 Apr 2007 8:39 Re: Is ESD protection essential? |
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As I have stated, ESD is a very common phenomenon and hence there has to be ESD protective circuits! I would be surprised if there are chips that go out without any ESD protection circuitry...
Generally the pads obtained from the foundry have ESD protection. But still the environment in which an IC operates deffers among all the ICs. Hence ESD/EOS tests are generally advisable for safety measures..
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memsgg
Joined: 01 Aug 2005
Posts: 34
Helped: 1
Location: cambridge, UK
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| 15 Apr 2007 8:54 Re: Is ESD protection essential? |
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| srieda wrote: |
As I have stated, ESD is a very common phenomenon and hence there has to be ESD protective circuits! I would be surprised if there are chips that go out without any ESD protection circuitry...
Generally the pads obtained from the foundry have ESD protection. But still the environment in which an IC operates deffers among all the ICs. Hence ESD/EOS tests are generally advisable for safety measures.. |
I know the ESD protection is very important for chip safety, but the chip I will design is to sense very weak current(lest than pA), so the leakage of ESD protection circuit shoud be less than pA, do you know, normally, how much current is the leakage from ESD protection?
If it is larger than pA, I should not include it in my design, do you know how risky it will be? In which stage will the damage happen, in foundry or when I measure it?
Many thanks
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leohart
Joined: 10 Nov 2006
Posts: 229
Helped: 12
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| 15 Apr 2007 13:23 Re: Is ESD protection essential? |
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| memsgg wrote: |
| srieda wrote: |
As I have stated, ESD is a very common phenomenon and hence there has to be ESD protective circuits! I would be surprised if there are chips that go out without any ESD protection circuitry...
Generally the pads obtained from the foundry have ESD protection. But still the environment in which an IC operates deffers among all the ICs. Hence ESD/EOS tests are generally advisable for safety measures.. |
I know the ESD protection is very important for chip safety, but the chip I will design is to sense very weak current(lest than pA), so the leakage of ESD protection circuit shoud be less than pA, do you know, normally, how much current is the leakage from ESD protection?
If it is larger than pA, I should not include it in my design, do you know how risky it will be? In which stage will the damage happen, in foundry or when I measure it?
Many thanks |
I'm concerning the same thing...As my application is also invovled with pA measurement.
I'm quite sure about there is test chip without esd protection in lab for experiment!
Some RF chip also don not use esd.
Maybe the necessity of esd also have sth to do with the internal circuitry,if the i/o pad connect to a internal circuitry which contain's two big oppsite polarity(p/n,n/p) diffusion,the esd is not so necessary.If it only connect to one big diffusion,either the positive or negative zap will no longer be a problem.
Correct me if I made mistake.Need all u guys' opinions
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rjainv
Joined: 18 Feb 2007
Posts: 147
Helped: 14
Location: Bangalore, India
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| 15 Apr 2007 19:53 Is ESD protection essential? |
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| I am not sure about Rf chips, but all chips I have seen so far, all the IO pads had ESD protection. Even direct drill power to analog cells sitting in middle of die had ESD protection circuitary hooked up.
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strennor
Joined: 09 Dec 2003
Posts: 66
Helped: 13
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| 16 Apr 2007 9:16 Is ESD protection essential? |
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I think you may remove ESD if the pad is only used for lab test and you won't bond wire to it in mass product.
Without ESD cell, the chip is easy to be damaged. But it is acceptable for lab test only.
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leohart
Joined: 10 Nov 2006
Posts: 229
Helped: 12
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| 16 Apr 2007 9:26 Re: Is ESD protection essential? |
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| strennor wrote: |
I think you may remove ESD if the pad is only used for lab test and you won't bond wire to it in mass product.
Without ESD cell, the chip is easy to be damaged. But it is acceptable for lab test only. |
THX,any points to prevent pad with esd from being damaged as much as possiable?Like before touch the chip,touch metal water pipe or wearing a electrostatic ring....
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