HMVCA1b

Due soon. Dual linear temperature independant, DC and audio, precision low noise voltage/current controlled amplifier.

Features

• • Two VCA's in one small package

  • +/-12V to +/-15V supplies

  • Low noise, wide dynamic range, excellent audio properties

  • Linear control voltage/ control current

  • Current or voltage output

  • Excellent DC performance

  • Temperature independent

  • Current or voltage signal input

  • Ground referenced summing node input

Transfer Functions

The HMVCA transfer functions are very simple to work with.

Current I/O

I(out)=k*I(in)*I(ctrl) k=10^4*(|V-|/15V)

Therefore if V- = -15V:

I(out)=10⁴*I(in)*I(ctrl)

This means for a control current range of 0-100uA the gain of the amplifier can be varied from -120db to 0db (effectively 0 to 1).

The signal output current can be converted to an output voltage using the on chip low offset, low noise operational amplifier, making V(out)=-R*I(out).

The signal input is a virtual ground summing node and can be fed from an input voltage with a resistor, making I(in)=V(in)/R.

The control input is a virtual ground summing node and can be fed from an input voltage with a resistor, making I(in)=V(ctrl)/R.

All current inputs and outputs should be limited to +/-400uA max.