[time-nuts] Super Regulator links

Grant Hodgson grant at ghengineering.co.uk
Fri Dec 14 05:30:41 EST 2007


Torex make some very nice low noise regulators; the XC6204 series has 
been around for some years now and appears to offer much lower noise 
levels than the 723 :-

http://www.torex-europe.com/products/range/125

Click on 'Technical Diagrams' to see the noise plot of the 3V part - sub 
1uV /rtHz at all frequencies above 100Hz.  One has to assume that the 
noise specification for the uA723 is per rtHz, in which case the Torex 
part has lower noise.  The uA723 has higher ripple rejection though.

The Torex XC6204 is specifically intended for noise-critical 
applications such as oscillators, PLLs and the like - it's not really a 
general purpose regulator like the 723.

Torex parts are available in the UK (and maybe elsewhere) from Farnell, 
other distributors also stock them.

I suspect that lower noise regulators are now available.

regards

Grant


John Miles wrotre :-

What are some of your favorite low-noise regulators?  When I made the 
remark about the uA723, I was specifically thinking of its performance 
compared to the LT1762.  With Cref=5 uF, the uA723's output noise 
voltage is rated at 2.5 uV from 100 Hz to 10 kHz.  The LT1762, which 
seems to be among Linear's quietest parts, is rated at 20 uV from 100 Hz 
to 100 kHz, with external bypassing that places most of the noise at 
lower frequencies.  Snake oil or not, that's 18 dB less noise from the 723.

There are various hacks like Wenzel's that can clean up after a noisy
regulator, but if there are quieter fully-integrated solutions out there 
I'd like to hear about them.  Posted back to the list in case there are 
other views on the subject...

-- john, KE5FX



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