AD8184 Crosspoint failure

Question

I've used the AD8184ARZ for years now. The device it's used in, is a simple Video Audio 4x1 switcher. About a year ago a customer started complaining abou the AD8184 failing on input 1. I suspect static zapping the input as video is plugged in. I've attached a partial schematic. The AD8184 is powered by +-5V, The control lines are TTL from a Microcontroller. The enable (EN) is set low (always enabled) via the Micro. 
 The customer installed these in an automated Set-Top Box (Cable Receivers) test bed. They plug in these STB's and verify video through screen captures, ect. The problem is out of 100 4x1 switchers, and 1000 STB's tested, about a half dozen 4x1 switches will fail every month. Replacing the IC's is becoming a serious problem. I've verified the video sources plugged in are "Standard" That is 1V-p Video at 0VDC, Clamped Video (.2VDC), and Computer based Composite video (0.6VDC)

FormerMember · Accepted Answer

mcurtin, 
 Two things cause me concern. 
 -- Do you really need 100 uF?? to go low enough? Would 10uF work or 1uF?? 
 I can see the cap getting charged up to xx volts, and when the supplies go away, the cap discharges 
 through the ESD diodes. 
 The HBM is 1500V, which is not super high, but o.k. 
 -- The other thing to watch out for is power supply sequencing. Scope out V+ and V- on turn on 
 and also on turn off. The part is on XFCB, so this is probably not a problem. 
 If this has been going on for awhile, you need to go back to where you bought the parts, and 
 if they are an authorized distributor, they will help you fill out a Failure analysis request. 
 Once we decap the part, we can tell if the input metalization is melted that you have a system 
 problem or we have a problem. 
 Harry)

EZAdministrator · Answer

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AD8184 Crosspoint failure