EMRFD Message Archive 2027

Message	Date	From	Subject
2027	2008-09-07 21:43:05	David Brainerd	DBM driven by PECL
Has anyone driven a DBM with the output of a PECL flip-flop? Looks like it might be just about the right level for a +7dbm DBM. Dave - WB6DHW <http://wb6dhw.com>
2028	2008-09-07 21:58:55	brainerd@wildblue...	Re: DBM driven by PECL
That should read LVPECL flip-flop. On 8 Sep 2008 at 4:43, David Brainerd wrote: > Has anyone driven a DBM with the output of a PECL flip-flop? Looks > like it might be just about the right level for a +7dbm DBM. > Dave - WB6DHW <http://wb6dhw.com>
2033	2008-09-08 13:21:41	Gary Johnson	Re: DBM driven by PECL
LVPECL (or PECL) provide an output swing of 700-800 mV p-p into 50 ohms, on each of their complementary outputs. That works out to 2.0 dBm. You could use a conventional 1:1 xfmr to roughly double the power output by taking advantage of the differential outputs. But Zout for PECL is about 3 or 4 ohms, so in any case this would certainly not look like a 50 ohm source. That alone makes it undesirable as a DBM driver unless you back-terminate it and give up half the output power. Note that you also need to dc terminate each PECL output to about Vcc-2 V. That could be provided thru a center-tap on the xfmr primary. Nice app notes