Digital controlled VGA

Frank Mikkelsen 19 years ago

Hi group

I am looking for an digital controlled variable gain amplifier with BW >

200MHz.

The amplifier had to have min. 256 steps and should be used in an 50R system therefore impedance match on in- and output are preferred. Max output power

10->20dBm.

I can´t find any integrated amplifier there match these requirements. My best choice is AD8368

formatting link

and then use a DAC for the digital control.

Have I missed some? Any suggest will be appreciated very much

Thanks in advance

Frank

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slebetman 19 years ago

The term you're looking for is PGA: Programmable Gain Amplifier. Google it, just use "programmable gain amplifier" instead of "PGA" otherwise you'll get lots of golf and FPGA/CPLD links.

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Nico Coesel 19 years ago

I've looked for similar devices, but can't find them either (at a reasonable price). I suppose a 200MHz amplifier and an RF attenuator ($$$) or building your own from a transistor array and a DAC are the way to go.

Reply to nico@nctdevpuntnl (punt=.) Bedrijven en winkels vindt U op www.adresboekje.nl

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Jim Thompson 19 years ago

I've done several designs for (custom ASIC) WiFi repeater chips... with 0.25db steps, but I don't know of any off-the-shelf.

...Jim Thompson

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Nico Coesel 19 years ago

I think there is a gap in the market when it comes to high speed controlled gain amplifiers. The best (affordable) ones I've seen use an controlled attenuator and a fixed gain amplifier. This method does make me worry about noise. Something low noise and no gain/bandwidth relation would be very neat.

Reply to nico@nctdevpuntnl (punt=.) Bedrijven en winkels vindt U op www.adresboekje.nl

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