[time-nuts] Thunderbolt Supply

Achim Vollhardt avollhar at physik.uzh.ch
Sun Feb 13 13:44:37 UTC 2011


Dear Bert and all,

maybe I missed it, but how can a linear regulator filter out transients 
from a switched PSU? The cited LT1764A has less than 30dB Suppression at 
100 kHz getting worse for higher frequencies.Even the famous 7805 had 
only 50 dB suppression. For going to a real clean PSU, I would expect 
some old-school filtering and screening should be fine.. or am I wrong?

A classic 50/60 Hz all linear PSU has a bad efficiency, but very little 
high frequency spurs to care about. For my current project (GPSDO with 
double oven HP10811), I will only use those.. even the classic LED 
7-segment display I am planning to use will not use multiplexed mode but 
quasi-static (1 Hz update rate only).

Regards,
Achim




More information about the Time-nuts_lists.febo.com mailing list