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

How to improve low frequency PSRR of bandgap reference circuit in PCB

Status
Not open for further replies.
B

bhl777

Full Member level 6
Joined
Sep 30, 2008
Messages
363
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,296
Activity points
5,140
Hi all, I have a bandgap reference circuit on PCB board. Internal circuits cannot be changed, but external components can be freely chosen.
The measured low frequency(up to 1kHz) PSRR is around -15dB but simulation results showed around -50dB. I am not sure if any external circuits can help about this. Can anyone advise?
I did look into this thread, https://www.edaboard.com/threads/52940/, but it seems it deals with high frequency PSRR. In my case, low frequency PSRR is more important, and do I need to do something in power supply to improve it?
Thank you!
 

Do You include in your simulations bonds and pcb paths inductance? After full chip RC extraction the PSRR is also quite good?
 

Dominik Przyborowski said:
Do You include in your simulations bonds and pcb paths inductance? After full chip RC extraction the PSRR is also quite good?
Click to expand...

Hi Dominik, I did not include bondpads and pcb paths inductance in simulation. If they are the problems causing bad low frequency PSRR, how can I improve it on board? Thank you!
 

crutschow said:
Post your schematic and simulation.
Click to expand...

That is traditional first order bandgap, with opamp and cascode current mirrors to generate PTAT current. Simulation with the schematic (not post-process simulation) is like this
PSRR.jpg

The measurement setup is similar to what used to be done for power supply audio susceptibility, like this
measure_psrr.jpg

Thank you!
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top