We have a project with differential output DDS and need to create 2 channels with programmable amplitude. Could somebody recommend some good RF gain/attenuation buffering IC?
The specs I need to target are:
7 dBm to +23 dBm range, 50 Ω impedance
-13 dBm to +7 dBm range, 50 Ω impedance
On the DDS, I can vary the output full scale current with a resistor to get full scale output voltage of 62.5mV to 500mV into a 50 Ω load. You can see that I might be able to make it just with the current adjusting. I have not built the board yet and don't know how good this approach is. Still, any good chips out there?
dBm = 10*LOG10 (V^2 / (R * 0.001)
I have to add some precision. I can only adjust the power that goes into the two channels simultaneously. I need to adjust the two channels independently, so need to put two programmable gain/attenuation channels.
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In reply to Frank Eory2:
Can you clarify further on your bandwidth? You only mention a bandwidth of 25MHz in the title, however you say you are looking for an RF amplifier. We have a few RF VGAs that can be found here that might be able fit your requirements:
In reply to Hasan Babiker31:
Thanks for you reply. We expect to use the DDS to create signals from around 10MHz (could be lesser than that) up to 25MHz.
The DDS is differential output. I am putting an LC fitler network after it.
How about a device such as the LMH6517, this is a two channel device with the ability to vary the gain of each channel independently.
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