Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

LM317/337 ripple/noise/oscillation
LM317/337 ripple/noise/oscillation
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 1st February 2018, 07:10 AM   #11
dotneck335 is offline dotneck335  United States
diyAudio Member
 
Join Date: Dec 2012
I saw a study that recommended a load for three-pin regulators of 220uF, with ~100mΩ ESR; also 220uF across the voltage adjustment resistor. This provided the best noise and ripple characteristics. Also note that the Linear Technology LT317/337 regulators have definitely better datasheet specs than the typical T.I. LM317/337s----about 16db better ripple rejection and about 10db less noise. They're more expensive---about $2.50 each, while T.I.s are 50; but for DIY projects where you're only using a few, it's money well spent.
  Reply With Quote
Old 1st February 2018, 07:18 AM   #12
Keruskerfuerst is offline Keruskerfuerst  Germany
diyAudio Member
 
Keruskerfuerst's Avatar
 
Join Date: May 2007
Location: Germany
What is the distance between the input pin (power) of LM317 and the 100nF ceramic?
And also the distance of output pin (power) of the LM317 and 100nF ceramic/220 electrolytic?
  Reply With Quote
Old 1st February 2018, 07:25 AM   #13
belyakove is offline belyakove  Netherlands
diyAudio Member
 
Join Date: Jan 2017
Location: Amsterdam
Input ceramic sits almost right on the input leg of regulator and output capacitor is around 1.5-2cm away from the output leg. Here are several photos of the PSU board.
Attached Images
File Type: jpg IMG_7022.jpg (902.2 KB, 405 views)
File Type: jpg IMG_7023.jpg (849.9 KB, 328 views)
File Type: jpg IMG_7024.jpg (792.6 KB, 308 views)
File Type: jpg IMG_7025.jpg (789.0 KB, 296 views)

Last edited by belyakove; 1st February 2018 at 07:27 AM.
  Reply With Quote
Old 1st February 2018, 08:45 AM   #14
Keruskerfuerst is offline Keruskerfuerst  Germany
diyAudio Member
 
Keruskerfuerst's Avatar
 
Join Date: May 2007
Location: Germany
The capacitor (ceramic/electrolytic) should be less than 1cm away from input pin of LM317.
The capacitor ceramic and electrolytic (470uF) should also less than 1cm away from the output pin of LM317.
  Reply With Quote
Old 1st February 2018, 09:07 AM   #15
Keruskerfuerst is offline Keruskerfuerst  Germany
diyAudio Member
 
Keruskerfuerst's Avatar
 
Join Date: May 2007
Location: Germany
Can you post the PCB layout?
  Reply With Quote
Old 1st February 2018, 09:48 AM   #16
belyakove is offline belyakove  Netherlands
diyAudio Member
 
Join Date: Jan 2017
Location: Amsterdam
Here's the PCB layout
Attached Images
File Type: jpg PSU_PCB.jpg (280.1 KB, 316 views)
  Reply With Quote
Old 1st February 2018, 09:53 AM   #17
Keruskerfuerst is offline Keruskerfuerst  Germany
diyAudio Member
 
Keruskerfuerst's Avatar
 
Join Date: May 2007
Location: Germany
The layout is not correct.
  Reply With Quote
Old 1st February 2018, 10:38 AM   #18
belyakove is offline belyakove  Netherlands
diyAudio Member
 
Join Date: Jan 2017
Location: Amsterdam
Can you please explain what is not correct here and how it can be improved? I'm pretty novice so trying to learn things.
  Reply With Quote
Old 1st February 2018, 12:02 PM   #19
Keruskerfuerst is offline Keruskerfuerst  Germany
diyAudio Member
 
Keruskerfuerst's Avatar
 
Join Date: May 2007
Location: Germany
The distance from capacitor (PIN +) to PIN 3 of LM317 must be less than 1cm.
The same for PIN 2 (output PIN).
And you also add diodes (like 1N4001) from output to ground (anode to PIN 2)
And from output to input (anode to input (PIN3))
Have a look at the datasheet for that. Here: https://www.google.de/url?sa=t&rct=j...OPMAJjbmXwAgfV

Last edited by Keruskerfuerst; 1st February 2018 at 12:14 PM.
  Reply With Quote
Old 1st February 2018, 12:20 PM   #20
chip_mk is offline chip_mk  Macedonia
diyAudio Member
 
Join Date: Jul 2005
Location: Skopje, Macedonia
Quote:
Originally Posted by belyakove View Post
Tried with 1k resistor (metal film if it's important) and peak to peak signal with it is 16mV
Did you measured free-standing 1k resistor (not connected to this PSU)?

This is far more than predicted 80uV Johnson noise few posts above. Perhaps an osciloscope issue?
  Reply With Quote

Reply


LM317/337 ripple/noise/oscillationHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Reduce SMPS ripple noise for PreAmp? forestsgump Power Supplies 42 15th February 2018 04:01 AM
Check my figures for LM317 ripple dotneck335 Power Supplies 26 15th November 2017 11:10 AM
AMC 3030 annoying ripple noise SimpleMind Tubes / Valves 8 18th March 2017 07:53 PM
Low Noise/Ripple 24Vdc 12 Psu (100mA) mrr76 Power Supplies 4 23rd July 2013 04:17 AM
Borbely PS has 5 uV noise and ripple - little or much? Sigurd Ruschkow Power Supplies 16 2nd April 2005 11:38 AM


New To Site? Need Help?

All times are GMT. The time now is 11:44 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki