Hi, NS gives some informations about improvements in their AN-173.pdf http://www.national.com/ds.cgi/LM/LM117.pdf Audio freaks are discussing it in http://www.diyaudio.com/forums/solid-state/28978-improving-lm3x7-regulator-circuit.html Is that what you are looking for?
73 Arnold On Thu, 25 Feb 2010 11:22:02 +1300, Bruce Griffiths wrote: >You can improve the performance of the LM723 if one substitutes an LM329 >for the internal reference biased from the regulator output. >The trick is to use the internal reference for startup and decouple it >with a diode or similar once the LM329 achieves its nominal output. >Currently, there appear to be 2 variants of the LM723 one (made by >National) that uses a noisy bandgap reference and another variant that >actually uses a quieter zener reference. >Bruce >Brooke Clarke wrote: >> Hi neville: >> >> My old Gibbs rack mount 5 MHz standard used the LM723 linear >> regulator. I believe it's one of the lowest noise regulators you can >> use. >> http://www.national.com/mpf/LM/LM723.html#Overview >> >> Have Fun, >> >> Brooke Clarke >> http://www.PRC68.com >> >> >> Neville Michie wrote: >>> Hi, >>> I remember a reference, probably by Bruce, that LEDS provide a low >>> noise voltage reference. >>> I am proposing to build a voltage regulator for a thermally >>> controlled LPRO rubidium oscillator, >>> with the voltage regulator being mounted on the 0.5 inch thick >>> aluminium heat sink plate. >>> The LEDS would also be mounted on the plate, which has controlled >>> temperature. >>> The LPRO has internal voltage regulation, and by running it at ~40C >>> and 18Volts, the thermal >>> flux within the unit is minimised as is the power demand. >>> What I want to know is if a LM317 running on a stack of LEDs driven >>> by the LM317 output >>> would provide a low noise power source? What would be better? >>> >>> cheers, Neville Michie >>> _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
