I was checking for wideband LNA from 100Hz to 900 MHz. I found AD5530 as a useful choice. I think that is the sole of that type. Does AD has a similar wideband amplifier with more gain .( > 20 dB)
We don't have anything in that form factor (i.e. 50 ohm single-ended in/out) that has a gain of 20 dB and covers that frequency range. One option that might fit would be a differential amplifier. ADL5565, for example, will operate down to dc and has a 3 dB bandwidth of 6.75 GHz (www.analog.com/adl5565). It's optimized for differential drive but the input can be driven single-ended.
When using ADL5530 for wideband operation can I use a resistor instead of an inductor for DC bias. My operation is from 500 Hz to 500 MHz and I assume with inductor in place, there will be some selectivity and may be I wont get the sufficient gain peformance throughout my band specially at the edges..
it is difficult to go low frequencies with those kind of amps.
i did the a similar thing in the past.
yes you can replace inductor with resistor, but adl5530 consumes 110mA, so don`t forget to calculate the power rating of the resistor.
and, your gain will degrade due to resistor loss. lower bias resistor means higher loss. higher res means more power dissipation on the resistor thus larger resistor.
you will have to increase the values of DC block capacitors. For 500Hz you will be needing something as high as 10uF.
moreover, is the part tested at 500Hz during production or design stage?
if i were u, i would use the diff amp ADI guy suggested at above post. he said they don`t have a device covering the freq range and gain you need, most probably none of the vendors has such device.