Re: 4420 driver ICs

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Jan Wagner <jwagner-at-cc.hut.fi> 


On Wed, 31 Mar 2004, Tesla list wrote:
 > Original poster: Fucian-at-aol-dot-com
 > Ive been having weird trouble with my 4420 fbsstc...They keep dying, for no
 > apparent reason...I just had one die once i put the circuit into a grounded
 > metal enclousre...It just stays on w/o even having a signal to turn it
 > on...Another died after not having ANYTHING done to it...It worked the
 > night before, i turned it on today, absolutlely nothing...ANother just
 > decided to give 1cm sparks reguardless of the power i gave it...Frequcny
 > was measured at 60hz?

Have you added the proper capacitors between ground and Vcc/Vdd right
next to the chip? 1 electrolytic + some ceramics or plastic caps?
Depending on your board layout, leaving out those local RF decoupling caps
on the supply rails can lead to really nasty spikes on the chip when it
'runs', could be high enough to zap them (absolute max supply voltage=20V).

regards,

- Jan

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