[time-nuts] Low noise power supply

[J.D. Bakker]

At 16:41 -0500 08-03-2011, EWKehren at aol.com wrote:
>There is an interesting article in the March 2011 Electronic Products
>magazine "design an ultra low noise supply for analog circuits. It is a
>combination of switcher and LDO's and written by P Hunter TI so it 
>may also  be available on their site.

This one, I presume: 
<http://www2.electronicproducts.com/Designing_an_ultra_low_noise_supply_for_analog_circuits-article-fapo_TI_mar2011-html.aspx> 
? Bit of a shame to use LDOs and then still drop 50% of the output 
voltage. Also, Fig 2 is meaningless without a measurement bandwidth 
spec.

There are other ways to get a cleaner bipolar supply from a switcher, 
several of them simpler than what's shown here. You could take a 
SEPIC/Cuk hybrid, or pick a switcher that allows you to trade 
efficiency for switch slew rate like the LT1533. Some useful 
techniques are documented in <http://www.linear.com/docs/4159>.

JDB.
[not affiliated with Linear Tech other than being a satisfied customer]
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