[time-nuts] Performance of 74LVC series ICs

[Bob Camp]

Hi

The question is always “good isolation compared to what?”. 

If you are expecting 180 db of isolation on a SOT-23 package at 10’s of MHz, it’s
not going to happen. It’s also not going to happen with a practical pc board layout
even without the SOT-23 involved. 

If something around 120 db is “good isolation”, then yes you can do that with a 
pair of the SC-70 parts and a good layout. In this case the test was at 10 MHz.

Bob

> On Jun 9, 2015, at 12:26 AM, Andy <AI.egrps+tn at gmail.com> wrote:
> 
>> 
>> I have something of a follow up question. How good is the isolation inside
>> these devices (74LVC, SOT-23 package) between gates?
>> 
> 
> Maybe it's just me ... but I wouldn't trust the isolation to be good.
> Apart from on-die coupling, they share the same power/ground leads, however
> short they are.  So just getting power and ground from the board onto the
> die, they would be corrupted by what happens in the other gate and its load
> (L*di/dt).
> 
> Andy
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