Part Number: LME49725
I am looking for a replacement for this device, here are the application details for an analog synthesizer:
The most critical application it's used in is an exponential converter, which takes a 1v/octave input and outputs a .25v/kHz signal. This circuit works by allowing a capacitor to discharge through a resistor for a duration that's proportional to the input voltage. The final voltage is then applied to a sample and hold. In order to meet my accuracy target, fairly low input bias current and offset voltage are required, and in order to meet professional audio standards, very low THD+N are required, although it's not strictly necessary to meet both constraints in one part. Although the ultimate application is audio, a fairly high bandwidth is needed in the ramp generator and comparator stages in order to accurately track input signals near the top of the range (which generate very brief decay intervals, but nonetheless require the ramp to be quite linear).
