Programmable Gain Amplifier

Timo,

Unfortunately there's nothing that will do 59dB directly at that voltage supply. The PGA204 can do 60dB of gain, but it can only go down to 9V supply and has a gain bandwidth product of 1MHz. Also, 59dB of gain @ 30Mz bandwidth would result in a GBP of 26.7GHz which is pretty hard to come by :) 

However, one solution is to cascade multiple PGAs together in series to achieve an increased gain. An example of this can be seen on figure 61, page 22 of the PGA117 datasheet. The PGA117 which can be programmed for up to 46dB of gain via SPI and can be daisy chained together for higher gains. So If you put connect two in series you could get 92dB of gain, 3=138dB, etc. However, the unity gain bandwidth is still only 10MHz, so even if you operated them all at a very low gain you still wouldn't get there.

Another option if you don't need the full 0dB to 59dB range, you could include a pre-amp with a fixed gain or externally set gain and use a PGA with a smaller range. An example of this could be seen in figure 66, page 27 of the THS7001 datasheet. Again, the power supply is an issue here as the THS7001 only goes down to 9V.

Unfortunately there's not a real good solution that captures all of your design requirements. If you can loosen up any of the specs, then you have a couple options at least.

Hope this helps.

Regards,
Luke LaPointe
High Speed Amplifiers