On Sun, 12 Oct 2003 15:23:22 +0100, Joe McElvenney
wrote:

Has anyone a pointer to the RF output impedance of the 74HC
series gates (at about 10MHz)? I have a few inverters/buffers
left over in a package and thought of using them stacked to drive
an output port via a simple matching network. I've seen this done
before and have simulated it myself but would like it spelled
out.

How about using an open collector device like the '06 or '07 and put a
parallel resonant circuit from the output to V+ (which might be Vcc or
some lower or higher voltage depending on your need and buffer voltage
rating) and analyze this as a class C amplifier stage ?

If you have multiple OC inverters, run two out of phase into a centre
tapped transformer (CT to V+) and put the resonant circuit on the
secondary. Again, V+ could be adjusted to give required impedance and
power levels. This circuit would have good symmetry, since the
impedance would be the same on both half cycles, thus reducing the
even harmonics, thus, the third harmonics would be the first one to
worry about, if you need sinusoid output.

Paul OH3LWR