José, 14 mA seems a bit high... but you may check the other pin voltages, too.
The UPC2749TB is available here: http://www.mouser.com/ http://search.digikey.com/ Digikey has a sales office in Germany, so you might save on shipping. It's probably easier to ask NEC for 2...3 samples than to order a single device from a supplyer... ...or try it here: http://www.msc-ge.com/frame/d/wir/inhalt_hig.html ... they are also in Madrid and in Barcelona :-) http://www.msc-ge.com/frame/d/wir/inhalt_hig.html How sounds that? Adrian Jose Manuel schrieb: > Thank you very much Bruce and all who replied my previous message, > > > According to measurements made with multimeter I think the MMIC is damaged, > because it´s consuming more than 10mA, when its maximum specified current, > at 3V, is 8mA, and the typical 6mA; maybe some of its internal transistors > are shorted. The measured supply voltage at pin 6, mid point of 270 and 68 > ohms resistors, is 2.78V. > > The input transistor is supplied with 2.61V and biased with 0.69V, the > current is 8mA, so I think it´s OK. > > By the way, my Z3801 only delivers 4.67V to the antenna connector. > > Datasheet of the MMIC can be seen here: > http://www.necel.com/microwave/en/pdf/P13489EJ3V0DS00.pdf > > Now my problem is where to purchase one of these devices ;-) > > > > Best regards....José, EA1PX > > > > > > > > > ----- Original Message ----- > From: "Bruce Griffiths" <[EMAIL PROTECTED]> > To: "Discussion of precise time and frequency measurement" > <[email protected]> > Sent: Tuesday, July 22, 2008 7:44 AM > Subject: Re: [time-nuts] HP58504A antenna > > > >> Correction: >> Resistor values used are probably: >> >> 100 = 10 ohms >> 560 = 56 ohms or is it 680 = 68 ohms? >> 101 = 100 ohms >> 121 = 120 ohms >> 181 = 180 ohms >> 221 = 220 ohms >> 271 = 270 ohms >> >> >> >> Thus the total resistance from the 5V supply to the output terminal of >> the input device is actually = 220 + 10 + 10 = 240 ohms. >> Equivalent resistance from input device "source" terminals to ground = >> 90 ohms. >> Voltage divider for Vcc of MMIC is 56 ohms from 5V is series with 270 >> ohms to ground nominal current ~ 15mA + 6mA? for MMIC, total ~ 21mA. >> Input device if shorted would have a current drain of 5V/(90+220 + 10 + >> 10) ~ 15mA. >> >> Thus measuring the dc output of the input device and/or measuring its >> power supply current is required to assist diagnosis. >> Some pHEMT devices have an absolute drain source voltage limit as low as >> 3V so the operating drain source voltage of the input device may only be >> 1/2 that. >> Typical MMICs have a somewhat larger dc voltage on the output. >> >> Bruce >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> -- >> No virus found in this incoming message. >> Checked by AVG. >> Version: 7.5.526 / Virus Database: 270.5.3/1564 - Release Date: 21/07/2008 >> 6:42 >> >> >> > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
