PSRR

[Thomas Mann]

How can I simulate the PSRR (Power Supply Rejection Ratio) with Cadence ?
Is the AC-Difference-Analysis choosing the nodes Vdd and Vout the right way
to simulate it ?

 

[Andrew Beckett]

Not sure what you mean by AC-Difference-Analysis.

I would tend to use XF analysis - that way you can tell it the output of the circuit, and then
find the transfer function from each supply or ground from the results of the same simulation.

You set up XF and tell it the output. When you plot the results, you can plot the transfer
function from any source in the circuit to the output (by default), or you can also
find the transfer function from any node or terminal to the output if you turn on
the appropriate option in the XF options form (can't remember what it is called now,
but it is fairly obviously named).

Andrew.

On Sun, 2 Nov 2003 16:33:18 +0100, "Thomas Mann" <webrider1000@gmx.de> wrote:

How can I simulate the PSRR (Power Supply Rejection Ratio) with Cadence ?
Is the AC-Difference-Analysis choosing the nodes Vdd and Vout the right way
to simulate it ?

--
Andrew Beckett
Senior Technical Leader
Custom IC Solutions
Cadence Design Systems Ltd

 

[Erik Wanta]

Thomas:
Run a XF analysis. You can get the data as follows. Note that Vp is
my positive supply voltage and Vn is my negative supply voltage.

PSRR-
db20(1/DATA("/Vn/PLUS" "xf-xf"))

PSRR+
db20(1/DATA("/Vp/MINUS" "xf-xf"))
---
Erik


Andrew Beckett <andrewb@DELETETHISBITcadence.com> wrote in message news:<i1maqvcsc802f4ivk2jvuer4bksnpeppqs@4ax.com>...

Not sure what you mean by AC-Difference-Analysis.

I would tend to use XF analysis - that way you can tell it the output of the circuit, and then
find the transfer function from each supply or ground from the results of the same simulation.

You set up XF and tell it the output. When you plot the results, you can plot the transfer
function from any source in the circuit to the output (by default), or you can also
find the transfer function from any node or terminal to the output if you turn on
the appropriate option in the XF options form (can't remember what it is called now,
but it is fairly obviously named).

Andrew.

On Sun, 2 Nov 2003 16:33:18 +0100, "Thomas Mann" <webrider1000@gmx.de> wrote:

How can I simulate the PSRR (Power Supply Rejection Ratio) with Cadence ?
Is the AC-Difference-Analysis choosing the nodes Vdd and Vout the right way
to simulate it ?