Re: Is the CLK0 pin of si5361a supposedly up to driving an HEF4013 direct?

Arv Evans


It depends...
Since you are driving a digital circuit the real requirement is to make that circuit toggle between
0V and 5V.  It it does that already then there is no problem.  If the digital circuit is biased at 2.5V
then only a few millivolts are needed to drive it between 0V and 5V output. 


On Sat, May 25, 2019 at 11:58 AM Chris Wilson <chris@...> wrote:
Chris Wilson 25 May 2019

I  have  been using my U3S as an exciter for LF and my friend uses his
in  the same way on MF. We take the CLK0 pin of the si5351a via either
a  100nF  or  220nF poly cap respectively direct to the input pin of an HEF4013
flip flop, which in turn is capacitively coupled via 100 or 220nF poly
caps  to  the  Class D amp FET driver IC(s).  I have now been told the
output of the si5351a is too low a voltage to drive from directly and
we  should  use a level converter to get 5V out. What are your thoughts
on  this please? It appeared to work OK as is... Thanks. The suggested
level converter is shown in the second schematic on this page.

If  the  feeling is this is desirable can we use a BS170 instead of the
2N7000 FET?

I  have  another  Class  D  amp  question  that  may  well be right up
Allison's  street,  but I'll create a separate (slightly off topic but
possibly interesting to the group) post.


Best regards,
 Chris                            mailto:chris@...

Best regards, Chris Wilson (2E0ILY)

Join to automatically receive all group messages.