Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Very low noise LDO 12V 500mA, something like LM317 ?

Status
Not open for further replies.
A

asrock70

Full Member level 4
Joined
Oct 9, 2010
Messages
201
Helped
5
Reputation
10
Reaction score
5
Trophy points
1,298
Activity points
3,252
I need power supply for precision analog design , +12V -12V, about 500mA, In short, something like LM317/337 but in very low noise version.
LM317 have RMS noise 0,003% f<=10kHz this is on 12V noise 360uV my design need about -20dB better -30dB less.
Is a newer low noise versin LM317?
Or recommend design with LM317 and active noise reduction circuit, ideally, any aplication note with noise calculation example.
 

LM317 is low noise. As a sugestion, why not use the low noise supply to only deliver to the portion of the circuit that really needs it - doubt the entire
circuit (that consumes 500mA) needs to have very low noise supply surely?
Then, you could use one of the super-low noise voltage reference ICs - although some of them are no better than the low cost TL431.
 

LM317 regulator has a noise of several hundred nV/Sqrt(Hz), this is not very low noise.
LM317/LM337 is low cost, for low noise and precision solution is need add some add circuit.
For more accurate and noise reduction we need voltage reference and amplifier for driving LM317
for example first section on my attachment.
AD8676 is quite expensive, low cost solution TL082,
Voltage reference , perfect is ADR441, but expensive, low cost TL431 is not very goot and low noise for this.
What do you think?
To further noise reduction can be added capacitance multiplier (right part)
But I do not know whether it makes sense to use with amplifier and voltage reference.
 

Attachments

  • Schematic Prints.pdf
    18 KB · Views: 129

Depends what he wants to do of course (which he didn't specify). For price-performance, TL431 is extremely low noise. As a single-component low noise
choice for higher loads, 317 is not bad either.
If he's building some instrumentation then sure, AD441 is a good choice ... but probably not needed to supply 500mA to all critical parts of the circuit.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top