Peak detector

[thefatmoop]

Hey everyone,

I'm trying to make a peak detector to detect the maximum amplitude of a 1kHz to 100kHz - possibly up to 500kHz sine wave. I followed the peak detection circuit here http://en.wikipedia.org/wiki/Precision_rectifier

but looks like my 4Mhz op amp http://www.adafruit.com/products/808 can only do peak detection up to about 20Khz or so. I'm using a 1N1418 for the diode.

Video demonstrating limitations
http://youtu.be/MzKXaQ6AHoM

So looks like I need an op amp with more bandwidth. If that's the case, does anyone know of a good/semi cheap 8pin DIP MOS (single rail psu) op amp to do the job?

[thefatmoop]

Here's what i've narrowed the choices down to so far
http://www.digikey.com/scripts/dksearch/dksus.dll?pv1291=862&FV=fff40027%2Cfff800dd%2C1140050%2C7b80007%2C7b80008%2C7b8000c%2C7b8000e%2C7b8000f%2C7b80010%2C7b80012%2C7b80015%2C7b8001a%2C7b80025%2C7b80027%2C7b80039%2C7b8004a%2C7b8009b%2C7b800ae%2C7b80101%2C7b8016c%2Ca4c0081%2Ca4c00a7%2Ca4c00e6%2Ca4c0123%2Ca4c0178%2Ca4c019a%2Ca4c01e0%2Ca4c01f0%2Ca4c024f%2Ca4c0268%2Ca4c0290%2Ca4c02b9%2Ca4c02e4%2Ca4c02ea%2Cc340002%2Cc340003%2Cc340004%2Cc340006%2Cc340009%2Cc34000a%2Cc34000e%2Cc34000f%2Cc340010%2Cc340014%2Cc340016%2Cc340019%2Cc340020%2Cc340021%2Cc340022%2Cc340023%2Cc340024%2Cc340025%2Cc340027%2Cc34002b%2Cc340030%2Cc340031%2Cc340033%2Cc340038%2Cc34003c%2Cc340042%2Cc340044%2Cc340045%2Cc340048%2Cc340049%2Cc34004d%2Cc340054%2Cc340061%2Cc34006b%2Cc34006c%2Cc34006f%2Cc340073%2Cc340077%2Cc340078%2Cc34007a%2Cc340090%2Cc340092%2Cc340093%2Cc34009d%2Cc3400a4%2Cc3400a5%2Cc3400a8%2Cc3400a9%2Cc3400ba%2Cc3400bb%2Cc3400be%2Cc3400c0%2Cc3400db%2Cc3400e9%2Cc3400eb%2Cc3400f0%2Cc3400f2%2Cc3400f3%2Cc3400f8%2Cc3400f9%2Cc340112%2Cc340113%2Cc340123%2Cf3c0002%2Cf3c0003%2Cf3c0006%2Cf3c000d%2Cf3c0018%2Cf3c0019%2Cf3c001a%2Cf3c001e%2Cf3c001f%2Cf3c007b%2Cf3c0094&k=op-amp&mnonly=0&newproducts=0&ColumnSort=0&page=1&stock=1&quantity=0&ptm=0&fid=0&pageSize=25

big link is BIIIIIIGGGG

[qno]

Use the improved version from Wikipedia.
It will have higher bandwith and ledd slew rate limits.