Re: [softrock40] Re: Cooked IC?
- I agree.I worked in satellite communications for 15 years. You MUST take ESD precautions all the time.Use an earthed bench mat, or build the circuit on an earthed metal plate.I also built nearly 1000 C-MOS PCBs as a sub-contractor to an electronics company, to my knowledge, none of them failed due to ESD problems.RegardsGeoff, G8BMI----- Original Message -----From: RaySent: Monday, April 28, 2008 5:28 PMSubject: RE: [softrock40] Re: Cooked IC?
It can most certainly do that much damage it can blow holes in the substrate and circuits and even fuse them together. ESD precaution is a serious matter and must be followed anytime you handle components and circuits. It is also possible to setup a latent failure with ESD so if it doesnt fail immediately it may later in time. I have worked with solid-state technology 45 years and always practiced ESD safety procedures; this is not a new science or phenonema. I have seen space-program devices and multi-million dollar computers fail due to ESD. Some of us consider certain types of IC designs as ESD proof and that is pure none-sense, some devices are hardier than others but in the modern world of micro-circuits nothing is 100% immune and most are not even close to being able to survive a static zap. Here is are some good pictures of what might happen due to ESD.
http://www.desco. com/PPT/ImagesOf ESDDamage. ppt#268,1,
So it can and does happen 100% caution is the only way keep the risk low.
I know that several people will jump on this mail with stories about static survival and how certain devices are immune and when a device is in the board it is safe. All I can say is that if you ignore the ESD procedures and get away with it count your self fortunate.
73, Ray, N0FY
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From: softrock40@yahoogro ups.com [mailto: softrock40@yahoogro ups.com ] On Behalf Of w7qjq
Sent: Sunday, April 27, 2008 11:45 PM
To: softrock40@yahoogro ups.com
Subject: [softrock40] Re: Cooked IC?
--- In softrock40@yahoogro ups.com, "Grant McDuling" <mcduling@.. .>
> Hi guys,
> I hit a prob with the softrock 40/80 v6.2 today. I picked it up to do
> some checks and ... zap... a static discharge. Now if I measure the
> resistance to ground from the 5V point, I get about 0.04 ohms; near
> dammit to a short. I guess I have cooked one of the ICs.
> Any ideas how I can tell which one?
> Grant VK4JAZ
Apply +5V from a supply that will source a few hundred mA to the +5V
test point for a few seconds.... the part that gets hot is the one
causing the problem.
However... I am not convinced that a static zap would cause such a low
resistance. Maybe a simple short from a solder splash or similar?
73, Sid W7QJQ
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