Need Amplifier

[cGr]

Hi..Firstly,thanks for your replies..
We decided that we will use another different amplifers because we changed our project..
We need 2 different ampliifers..
Firstly,we are getting signals in milivolts from ultrasonic sensors..We need to amplify it to 2.56 volt..In thıs signal,the important thing is not to phase shift..So the magnitude of the signal should be 2.56..So we are planning to use gain selectable amplifier..But We did not decide any amplifier model..Can you suggest anything about amplifers?

Second,we will get a signal from DAC,which peak between 0V-2.56V..We should amplify it to -10V - 10V signal...And we will drive this amplified signal to ultrasnic sensor..So the power of the signal should be enough for the driving ultrasonic sensor..
Do you have any suggestion about this?

Thanks for your helps...

 

[audioguru]

You need to amplify 40kHz with a voltage gain of about 512 times.
Audio opamps (TL072) have a full output up to 100kHz but their max gain at 40kHz is about only 100 times so two opamps are needed to share the total gain.
You will need a circuit to limit the max output to 2.56V.

The spec's for your ultrasonic transmitting transducer will show how much power is needed to drive it.

The ultrasonic transducers probably have resonances so their phase shift could be anything.

 

[cGr]

Thanks..I do not know how I can limit the output?Is there any circuit example that limit the max output to 2.56V..

 

[audioguru]

Thanks..I do not know how I can limit the output?Is there any circuit example that limit the max output to 2.56V..

Two resistors that make a voltage divider will limit the voltage when the output of the opamp clips.

 

[Gordz]

cGr you need to read this **broken link removed** and then consider your requirements. This will teach you about op-amp building blocks and their uses/configurations including feedback control for amplification.

 

[Hero999]

You need to amplify 40kHz with a voltage gain of about 512 times.
Audio opamps (TL072) have a full output up to 100kHz but their max gain at 40kHz is about only 100 times so two opamps are needed to share the total gain.

He could use the uncompensated TL070 which should be stable without a copensation capacitor when configured with a gain of 512. Granted, it's probably cheaper to just use the dual version but there are other options.

 

[cGr]

I will try it with TL072,thanks all..
And I will use a amplifier to drive the signal to the ultrasonic sensor,SRF04..TL072 is suitable for this purpose?Or Should I use a different opamp?