Other Parts Discussed in Thread: , LMH6321
Kind of parsing through some options for an imbedded power boost design where the old BUF634 and improved BUF634A show up regularly.
I had a comparison file set up anyway, and was astonished to not see any output impedance numbers in the BUF634 data sheet, kind of missing 1 of the 3 major I/O spec then (input impedance, gain, output impedance) for a buffer. The sim models for these are in various states, but the old 2011 BUF634 model being transistor based (as is the LMH6321) good sims might be expected. Here is a comparison of a zero output Io case of output impedance - these are both around 5ohms DC (the output stages are Class AB buffers, so that 5ohm maps to a DC bias current of about 2.6mA - seems reasonable). The BUF634 shows more resonance above 100Mhz which contributes to is rapid rolloff above 100Mhz into 50 or 100ohm loads.
In any case, the BUF634 PDS was recently updated, a spec line for at least DC Rout was missed - does the sim results seem credible?
