[SI-LIST] Re: ESD on center pin of 6VDC jack input.
- From: "Ken Cantrell" <Ken.Cantrell@xxxxxxxxxxxxxxxx>
- To: <Chandan.M@xxxxxxxxxxxx>, <si-list@xxxxxxxxxxxxx>
- Date: Wed, 19 Dec 2007 08:17:25 -0700
Chandan,
First I would reference the IEC spec for the specific rules. You want IEC
61000-4-2. Your answers will be in there. If the DC jack is not
accesible in normal use, then the area only needs to be swept with the
indirect discharge head. Your definition of "not accesible during normal
use" has to be the same as the spec. As I remember, if you recess the jack
an quarter of an inch to half an inch, you don't have to do direct contact
discharge, i.e., can you fit a finger in there. You can also put a "door"
(rubber housing) over the input. There are many ways to make it work.
There are two categories of devices for protecting your equipment downline
from the discharge, TVS's(transient voltage suppressor)also called
transorbs, and C/pi filters. The first is a fast triggering shunt to ground,
and the second is a low-pass filter that provides dB's of attenuation.
Power supplies typically use filters, I/O lines use transorbs(low shunt
capacitance).
The link below was the first hit on a Google search for transient voltage
suppressor.
http://www.microsemi.com/micnotes/125.pdf
Hope this helps,
Ken
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx
[mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Chandan M
Sent: Wednesday, December 19, 2007 6:48 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] ESD on center pin of 6VDC jack input.
Hi,
We are developing a handheld equipment, which can work on both battery and
AC/DC adapter.
AC/DC adapter is not mandatory to be connected while using the equipment.
Also there is no connection between the equipment and the earth while
operating on battery.
The DC jack is not accessible in normal use. where as it is accessible
with IEC test finger.
What I am wondering is, should we do contact discharge on the center pin
of the DC jack? And if we need not, I want to know the reason why we need
not?
I will be grateful if any can give some info on that.
Regards,
Chandan.
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