Re: 4420 driver ICs

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

Original poster: Fucian-at-aol-dot-com 

In a message dated 4/1/2004 9:23:38 PM Eastern Standard Time, 
tesla-at-pupman-dot-com writes:

>Relying heavily on the chip's ESD protection to handle it, right? ;-)
>
>I mean it seems a bit odd, with potentially 100V... x kV antenna signals
>going directly to the 4420 input pin. Now OTOH the 4420 datasheet shows
>internal protection diodes, so maybe your setup actually _does_ have
>some chances of working properly (?) :)
>
>To be on the safe side I'd probably add a 18V zener diode accross the
>chips Vdd and ground, and a very small 6.8V zener between the input pin
>and ground, so that the circuit is better protected from the kilovolts. Oh
>and a 100ohm..1kOhm resistor in series with the antenna, on the tc4420
>side.
>
>good luck,
>- Jan


I believe that the 1n60s will clamp the voltage going into the input pin of 
the 4420 at 12 volts...I went ahead and made an etched pcb and added the 
series resistor and zener just incase...

Matt