Re: LMH7220 docs

On Sat, 17 Jan 2009 19:20:16 -0000, "Andrew Holme" <ah@xxxxxxxxxxxx>
wrote:

I'm looking for an LVDS-output comparator to get a 3 dBm 40-70 MHz sinewave
into an FPGA as a clock. The National LMH7220 keeps popping up in searches.
It looks OK; but I wonder if anyone has a better suggestion? One slight
surprise was the waveforms at the end of this
http://www.national.com/an/AN/AN-1534.pdf application note. Firstly, the
frequencies illustrated seem a bit low. The comparator is specified to
1Gb/s. Secondly, the signals/probing on the cable don't look so great.

TIA
Andrew.


One very nice LVDS-to-LVDS part is the FIN1101. I'd bias both inputs
to, maybe +1.2 or thereabouts, AC ground one, and AC couple your
sinewave into the other. But in fact it works with one input grounded.

We pay about 80 cents. It's faster and cheaper than an official
"comparator", but it behaves like one.

John


.

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