VCA810: Designing a variable voltage gain amplifier

RaviKumar Jain

Part Number: VCA810

Hello Experts,

I want to design a variable gain voltage amplifier for lower cut-off frequency around ~500 Hz (upper limit doesn't matter) and gain of ~900V/V.

I am getting a DC offset which I don't want, and is this design practically correct?

Ravikumar

over 4 years ago

0 Sean Cashin over 4 years ago

TI__Genius 15146 points

Put a 8.8uF blocking capacitor in between the VCA810 output and the 50 ohm resistor to get rid of the DC offset at the output. Also, refer to Figure 30 of the datasheet. Yes the design is fine.

Best regards,

Sean

0 RaviKumar Jain over 4 years ago in reply to Sean Cashin

Prodigy 145 points

Thanks for the reply Sean.

I tried placing a resistor of 100Ω @ +IN of 2nd opamp, and it solved the problem of DC offset.

Is it good?

Ravikumar

0 Sean Cashin over 4 years ago in reply to RaviKumar Jain

TI__Genius 15146 points

If it removed the DC offset then it is good, unless you have anything else to ask. Why did you reject my answer?

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VCA810: Designing a variable voltage gain amplifier