¿ªÔÆÌåÓý

  1. HP-Agilent-Keysight-Equipment
  2. Messages
Single Messages Topics Expanded

Re: Info Need on a RF FET for a Agilent E4438C signal generator

 

¿ªÔÆÌåÓý

Hello Lothar It is a Fet. I does have a biasing system where is measures to drop over the Drain supply and then give bias to the Gate. The circuit does include matching network. I added a SHF-0189 in the circuit and it works but too low output for the High output option mounted. I can find traces on the Net over the M11X but only that it is a HFET.
The Fet is in the ALC loop so the amplitude is not really a problem as long as there is enough. I am afraid that is not the case. I wonder if a MMIC would work in the spot. I need one working from 250khz to 4Ghz. the 4 to 6Ghz path is another board so the Part only need to go to 4Ghz.
sorry no schematics over the E44XX series
best regards Peter OZ1LPR
Fra: [email protected] <[email protected]> p? vegne af Lothar baier <Lothar@...>
Sendt: 26. maj 2022 06:19
Til: [email protected] <[email protected]>
Emne: Re: [HP-Agilent-Keysight-equipment] Info Need on a RF FET for a Agilent E4438C signal generator
?

Do you have the schematic of the stage ?? if so can you share it ?

Let me render a few comments / thoughts on this :

  1. The first thing that needs to be established is whether the original part is a FET or a MMIC amplifier ,? you can tell by looking at the schematics , if there is a bias applied to both input and output or just the output of the block , if bias is only applied to the output than its more than likely a MMIC amplifier if bias exists on both gate and drain than it¡¯s a FET/HEMT !
  2. If the part is a FET than there should be matching as well as feedback networks present , since this is a stage operating over a wide frequency range resistive feedback between gate and drain will most certainly be required in addition to lumped input and output matching circuits
  3. Based on the gain and output power estimate you provided as well as the frequency range of the generator I question the assessment of this part being a FET and rather assume this being a MMIC as it would be hard to reach 20Db gain and 27dBm P1Db up to 4GHz
  4. If the part is a FET using matching networks it will be hard to find a drop in replacement , if you were to find a part in a SOT-89 package you will most certainly have to re-design the matching networks as S-parameters will be different

?

?

From: [email protected] <[email protected]> On Behalf Of Peter Hansen via groups.io
Sent: Wednesday, May 25, 2022 4:16 AM
To: [email protected]
Subject: [HP-Agilent-Keysight-equipment] Info Need on a RF FET for a Agilent E4438C signal generator

?

I am rapiring a E4438C generator. There is a FET shorted in the output of chain of the 4Ghz path. The FET is called M11X1005. I can see traces of it existing but no data. The SHF-0189Z can be used but not directly. The M11X1005 is using 6.5V on the drain but the SHF-0189 uses 8V and has higher gain and higher output.

Does anyone have either a M11X1005 Fet, data or a suitable repleacement.

I would assume something having 20dB of gain and +27dBm output.

best regards Peter
Join [email protected] to automatically receive all group messages.