[volt-nuts] Best reference after LTZ1000

Dick Moore richiem at hughes.net
Sun Aug 15 20:56:03 UTC 2010

The 34401 uses a reference from the National LM199 family -- I suspect they're selected in some first-order way to keep costs down. So using a few LM399's, each with a little series resistance in parallel driving a stable op-amp like an LT1150 chopper amp might be the best way to go. In my experience, the LM399 aging curve tends to flatten out significantly after about 10 hours of run time, so it doesn't take too long to get them pretty stable, and then using two or three or four is cost effective and tends to make a more stable system.

Dick Moore

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