Hello:
I'm starting to work on the design of various high voltage bias supplies for things like gaseous radiation detectors and I'm running into the issue of noise.
Of course, the best resource I could find on the topic is an App Note by Jim Williams, more specifically "Application Note 118: High Voltage, Low Noise, DC/DC Converters". There it is mentioned that a protection network as well as 40dB preamp has to be used before seeing the signal on the oscilloscope. I specially need this preamp, since my scope bandwith limits itself in the two lowest V/div and I want a 50Mhz bandwitdh noise measurement.
However, the HP-461A used by Jim goes for quite a bit on eBay. Is it easy to make with modern components an inexpensive 50Mhz amp with relatively low noise (also, I would like to use THT components)?
A superficial look at Mouser leaded to the LT1222, specifically designed to be stable at a gain of 10 with a BW of 50Mhz (from a GBW of 500Mhz).
Thus, could I cascade two non inverting amplifier stages like those shown in the Fig 1 of the Datasheet (without the clamping network)? Or are there any "traps for young players" (like myself) I'm missing?
I appreciate any help!
FAIL: I just came across EEVblog #572 Cascading Opamps For Increased Bandwidth and saw that the actual BW of the system would be 32Mhz! Thus, it seems like I need an even faster op amp. Any suggestions?