Sceadwian
Full Member level 3

I've been lightly toying with micro controllers for the last year or so as well as absorbing as much electronics knowledge as I can outside academia. The chips I'm currently using can generate square waves at 12mhz (50% duty cycle) and the newer one's I'm looking at using can go as high as 32mhz. At these frequencies a simple two pole RC filter works pretty well at filtering out the harmonics but after two poles the voltage I'm left with is only 775mv's I can probably get this up to a volt or so by tweaking my R/C values but I'd like to end up with a signal voltage of at least 3 volts at a 50ma load (or as much more as is practical) Are there DIP packaged OPAMP's that work at these frequencie's / current /gain etc? I'm still a little floored at the sheer amount of chips that are out there I'd appreaciate any pointers people could give me, especially about building such circuits on perfboard (hand soldered) for simple low level RF frequency generation.
Just to give a little more information. The I/O can source 40ma at 4 volts square. Would a low noise RF opamp fed directly from the I/O and the R/C afterwards be better? If the opamp could source enough current the voltage drop from the R/C filters will go down, which might be better than trying to amplify a weak signal.
Just to give a little more information. The I/O can source 40ma at 4 volts square. Would a low noise RF opamp fed directly from the I/O and the R/C afterwards be better? If the opamp could source enough current the voltage drop from the R/C filters will go down, which might be better than trying to amplify a weak signal.