On Sat, 19 May 2001, Aart wrote:

>Hello Peter,
>
>I do have the SIL 6 case, do you also have the pinlayout of that one?
>It's going to be used as a prescaler on a 50 Mhz frequentie counter, do you
>think that the range of the counter will be continue or will there be a gap
>in the range? (what is the Min. Frequentie of the U664B)

I have a foggy memory of seeing the relevant page in the datasheet of the
U664B at least 5 years ago and I think it is 70MHz or 50MHz to 1200MHz.
Maybe someone can correct me. With 50MHz there will be no gap (in theory).
I did not try to push the input stage on my counter design that far. I am
interested in 0-45MHz and 100MHz-4GHz. Currently I cover the upper side
using a UHF beat oscillator box. This makes for some doubtful results (I
have a pot on the mixer to set gain but it is very finicky). Any
prescalers for 4GHz ? (/256 if possible).

Beware that the U664B is a 'self oscillating design' (Telefunken
terminology 'selbstschwingend'). You will have output reading even with no
input signal. The input stage oscillates by itself but locks easily to any
input within spec (>50mV I think). The NEC chips do not oscillate. I am
currently using a NEC prescaler front end.

Peter

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