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LM2901: Variable Gain Amplifier Requirement

Madhu Sharma
Expert 2915 points
Part Number: LM2901
Other Parts Discussed in Thread: VCA810, OPA454, VCA820

Hi,

For one of my designs, I need to design a variable gain amplifier, which will give out  500HZ sine wave with maximum amplitude 45V and minimum 0.1V. 

The input to the amplifier is a 500HZ, 0 to 40V AC signal with constant amplitude of 40V.

The gain must be controlled by a processor as shown in below image ( both analog or digital control like I2C, SPI are okay).

The gain must be varied such that output amplitude will vary with 0.1V steps.

Please suggest me how to implement this kind of circuitry.

Thanks in advance.

Regards,

Madhu.

  • 0
    TI__Guru* 93105 points

    Hello Madhu,

    TI doesn't offer any ampifier products that will directly accomplish your high voltage, voltage-controlled amplifier (VCA) function. There are a few low-voltage VCA products such as VCA810 and VCA820, but these are intended for use with low-voltage supplies and comparable signal voltage levels. The high-voltage input voltage levels would have to be attenuated to use these devices. Then the output signal would have to be amplified with a high-voltage op amp such as the OPA454 to raise the amplitude to the needed output levels.

    The VCA810 and VCA820 are supported by TI's High-Speed Amplifiers group, while the OPA454 is supported by this Precision Amplifiers group.

    Regards, Thomas

    Precision Amplifiers Applications Engineering