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systematic offset & Random offset

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surianova

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systematic offset

hi!

just want to check between random offset and systematic offset in opamp for the below statements.. pls comment:

1. systematic offset can be simulated in normal simulation without doing any mismatch. It no need marte carlo simulation. Basically just get the output-vdd/2.

2. systematic offset basically just want to get the output vdd/2.

3. but systematic offset is not that important bcoz sometimes our output might be lower or higher than vdd/2 to bias other stage. Although output at vdd/2, can get the best gain from the opamp. Or in other word, purposely introduce systematic offset to get the desired output.


4. Random offset is cause by mismatch in the layout for the transistor need to be matched like current miror and input transistor.


5. Random offset must run with morte carlo analysis or mismatch the transistor manually.

pls comment statement above! thanks
 

op amp systematic offset tutorial

Hi
sytematic offset is depend on architecture
but mismatch can generate random offset in any architecture.
regards
 

random offset

1. systematic offset can be simulated in normal simulation without doing any mismatch. It no need marte carlo simulation. Basically just get the output-vdd/2..

its true that it is simulated in normal simulation.

2. systematic offset basically just want to get the output vdd/2.

i didnot understant this comment

3. but systematic offset is not that important bcoz sometimes our output might be lower or higher than vdd/2 to bias other stage. Although output at vdd/2, can get the best gain from the opamp. Or in other word, purposely introduce systematic offset to get the desired output.

You cant say this because its not much important in Vds mismatches of current mirror, but you cant neglect this mismatch in the input diffpair of an Op-amp

4. Random offset is cause by mismatch in the layout for the transistor need to be matched like current miror and input transistor.

yes.

5. Random offset must run with morte carlo analysis or mismatch the transistor manually.

yes
 
analysis of systematic mismatch in current mirror

1, System offset:
System offset occures duo to the non-idealities of a circuit even when all the elements of the circuit are perfently matched.
2, Random offset
Random offset occures duo to mismatches in supposedly matched devices.
 
random mismatches in layout

rajanarender_suram said:
1. systematic offset can be simulated in normal simulation without doing any mismatch. It no need marte carlo simulation. Basically just get the output-vdd/2..

its true that it is simulated in normal simulation.

2. systematic offset basically just want to get the output vdd/2.

i didnot understant this comment

3. but systematic offset is not that important bcoz sometimes our output might be lower or higher than vdd/2 to bias other stage. Although output at vdd/2, can get the best gain from the opamp. Or in other word, purposely introduce systematic offset to get the desired output.

You cant say this because its not much important in Vds mismatches of current mirror, but you cant neglect this mismatch in the input diffpair of an Op-amp

4. Random offset is cause by mismatch in the layout for the transistor need to be matched like current miror and input transistor.

yes.

5. Random offset must run with morte carlo analysis or mismatch the transistor manually.

yes
Click to expand...



how to check Systematic offset in normally simulation?
 

systematic offsets

surianova said:
rajanarender_suram said:
1. systematic offset can be simulated in normal simulation without doing any mismatch. It no need marte carlo simulation. Basically just get the output-vdd/2..

its true that it is simulated in normal simulation.

2. systematic offset basically just want to get the output vdd/2.

i didnot understant this comment

3. but systematic offset is not that important bcoz sometimes our output might be lower or higher than vdd/2 to bias other stage. Although output at vdd/2, can get the best gain from the opamp. Or in other word, purposely introduce systematic offset to get the desired output.

You cant say this because its not much important in Vds mismatches of current mirror, but you cant neglect this mismatch in the input diffpair of an Op-amp

4. Random offset is cause by mismatch in the layout for the transistor need to be matched like current miror and input transistor.

yes.

5. Random offset must run with morte carlo analysis or mismatch the transistor manually.

yes
Click to expand...



how to check Systematic offset in normally simulation?
Click to expand...

just use ideal component in spice and simulate output with zero input.It roots from the biasing of your circuit.
 

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