Charles, For the design I am contemplating, the accuracy of the X2 in not important, only the stability. For example, if the output of the X2 is 50uV low, I don't care so long as its always 50 uV low +/- a few ppm over time and temperature. The noise could be filtered but its must also be stable. Based on what I am hearing, the switched capacitor multiplier doesn't look promising.
Randy On Tue, Jul 22, 2014 at 5:40 PM, Charles Steinmetz <[email protected]> wrote: > Randy wrote: > > I agree that there are potentially some serious unknown issues with drift >> due to time and temperature due to changes in leakage current, charge >> injection, etc. I would think some serious characterization would be >> needed before this approach could be used. >> > > I have used LTC1043s in the voltage-multiplier configuration, and based on > that experience I believe you will find there are too many surprises hiding > there to reach your error budget. First, there are losses in the > conversion -- IME, even when driving nothing but the non-inverting input of > an LTC1050 chopper-stabilized opamp used as a follower, the output voltage > of an LTC1043 doubler is quite a bit (50uV or more) less than [Vin * 2]. > Second, the output of the 1043 + buffer is about 100x noisier than the > output of the same reference followed by a non-inverting gain-of-two > LTC1050 (on the order of 100uVp-p for the 1043 + buffer, about 1uVp-p for > the non-inverting gain-of-two amplifier in a 10Hz bandwidth, IME). Also, > the 1043 noise is not symmetrical, so different DC meters may give readings > that differ by 50uV from one another. > > If you try the LTC1043, I'll be interested to see what you find. > > Best regards, > > Charles > > > > > _______________________________________________ > volt-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/volt-nuts > and follow the instructions there. > _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
