[time-nuts] HP58504A antenna

[Adrian]

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" <bruce.griffiths at xtra.co.nz>
> To: "Discussion of precise time and frequency measurement" 
> <time-nuts at febo.com>
> 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
>>
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>
>
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