On Sat, 4 Jun 2005 08:56:56 -0700, "RST Engineering"
wrote:

It is worse than that, Wes. I fail to understand how a device can be
specified as X dB into a capacitive load. Last time I looked, a capacitive
load couldn't dissipate ANY power.

Jim, the OP said:

"And I have a LO source that give me an output of 2.5Vpp to a
capacitive load of 5pF at 40MHz."

No dB or dBm mentioned. This sounds like a CMOS device with limited
drive capability. That's why I suggest terminating it in 50 ohm,
assuming this doesn't destroy it, and see what kind of power it can
deliver.

Most likely, a buffer will be needed, although -16 dBm isn't much and
at that level it suggests that this is an active, not passive, mixer
and that it might be driven by a higher source Z okay.

Wes


Jim

This is pretty good, but errs when it states that 0 dBm is 1 mW in a
50 ohm system. This is the usual case, but it could just as well be
70 ohm, 600 ohm or 6 3/8 ohm.