How do lower the signal by 0.3v

[ahgu]

I have a signal in the range of 0.5v-2.7v, need to feed that to an ADC with a range of 0-2.5. What is a good easy low-noise precise way to lower the signal by
0.3V?

If I use a OPAM subtraction circuit, generate the 0.3v using a resistor divider, I was afraid the matching resistor error, and also supply noise from the dividor.

It is single supply opamp.


thanks
Ahgu

 

[IanP]

If you are afraid about precission use 0.1% resitors ..
There is no better and simpler solution than a 2-resistor voltage divider - go for it ..

Regards,
IanP

 

[windarray]

right the resistor divider is the best solusion...

you can use the small resistors with the buffer to achieve the low noise.

 

[lj053]

Can the resistor divider drive the ADC?
maybe you need a buf,but sigle supply.

 

[ahgu]

I can put a follower, not a problem.

for 100K ADC sampling, I wonder what kind of bandwidth I need for the OPAMP.
The opamp has 2 stages, follower--> subtraction--->ADC.

Also, what kind of LPF can I put on the circuit for 100K ADC sampling?

Any recommendation for what opamp to use?

thanks
Andrew

 

[Miguel Gaspar]

The opamp that you need depends of the fmax of the signal.