# Simple Sigma Delta Analog to digital converter

#### Raj_Singh

Joined Nov 26, 2023
31
I am trying to build a Sigma delta ADC and my circuit diagram is attached but I am getting some kind of inverted waveform. Can anyone help me to figure out where am I going wrong. I have given an AC sine between 0 to 5 V. The first graph is the output (g) and the second one is the output on the integrator.
Thanks!

#### ericgibbs

Joined Jan 29, 2010
18,646
I have given an AC sine between 0 to 5 V.
Hi Raj,
Your sine wave is swinging from -5v through +5v , it is not 0v to +5V
E

#### Raj_Singh

Joined Nov 26, 2023
31
Hi Raj,
Your sine wave is swinging from -5v through +5v , it is not 0v to +5V
E
I have given 0 to 5 V but I am getting a swing from -5 to 5....is there any other way to test my circuit

#### ericgibbs

Joined Jan 29, 2010
18,646
Hi Raj,
Check out this PDF.
E

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#### Raj_Singh

Joined Nov 26, 2023
31
Hi Raj,
Check out this PDF.
E
I do not want to build a quiet complex one but at first a simple one

#### crutschow

Joined Mar 14, 2008
34,044
I have given 0 to 5 V but I am getting a swing from -5 to 5....is there any other way to test my circuit
Given where?
In Spice you can generate a 2.5Vpk sinewave with a +2.5V DC offset which provides a 0 to 5V peak sinewave.

Last edited:

#### Raj_Singh

Joined Nov 26, 2023
31
Given where?
In Spice you can generate a 2.5Vpk sinewave with a +2.5V DC offset which provides a 0 to 5V peak sinewave.
It is the AC signal
It is a spice code
*Sin Wave
vin nin 0 sin (0 5 100 0 0)

#### Raj_Singh

Joined Nov 26, 2023
31
Can anyone let me know why my output wave is elevated

#### crutschow

Joined Mar 14, 2008
34,044
It is a spice code
What Spice are you using?
The AC definition should like like this:
SINE(2.5 2.5 100 0 0)
Can anyone let me know why my output wave is elevated
Post the Spice circuit schematic.

#### Raj_Singh

Joined Nov 26, 2023
31
What Spice are you using?
The AC definition should like like this:
SINE(2.5 2.5 100 0 0)
Post the Spice circuit schematic.
I am using AIMspice where the code is written...I don't draw the schematic like LTspice. The opamp is a very basic 5 transistor opamp

#### Raj_Singh

Joined Nov 26, 2023
31
Hello All,

I would like to know if the ADC is stable, or working based on the output waveform or do any of you have any suggestions to make it work more flawlessly.

#### crutschow

Joined Mar 14, 2008
34,044
I don't draw the schematic like LTspice.
Then post the schematic you used to generate the Spice file.
Schematics are the language of electronics.

#### Raj_Singh

Joined Nov 26, 2023
31
Then post the schematic you used to generate the Spice file.
Schematics are the language of electronics.
this is my schematic and in the above post that is my output

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