I had this problem when using some ultra low light imagers. They have NO PSRR, and the integration times were up in the 1-3 second range, so any noise on the pixel supply ended up in the image.
I used an ICL-9000 regulator which has ultra high PSRR, and I used a switcher running at a specific rate where the ICL-9000 has maximum PSRR. I also was very concerned with waste power, so the SMPS was set up for the output to be just high enough for the linear to stay in regulation. For this app you'd want a beefier reg, but search for high PSRR at the right current range and work backward from there. Layout is also HUGE in keeping switchers quiet. Most of what I do has switchers in the 1-5W range, and I only use two layer boards, but I get my noise low enough that both the pre-scan with GTEM and OATS site can't see whether I'm on or off. (conducted or radiated thru 15 GHz) -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of ewkeh...@aol.com Sent: Tuesday, March 08, 2011 2:41 PM To: time-nuts@febo.com Subject: [time-nuts] Low noise power supply 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. Bert Kehren _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
