VCA822

(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated is not implied. Exposure to absolute-maximum rated conditions for extended periods may affect device reliability.

The VCA822 is a dc-coupled, wideband, linear in V/V, continuously variable, voltage-controlled gain amplifier. It provides a differential input to single-ended conversion with a high-impedance gain control input used to vary the gain down 40dB from the nominal maximum gain set by the gain resistor (RG) and feedback resistor (RF).

The VCA822 internal architecture consists of two input buffers and an output current feedback amplifier stage integrated with a multiplier core to provide a complete variable gain amplifier (VGA) system that does not require external buffering. The maximum gain is set externally with two resistors, providing flexibility in designs. The maximum gain is intended to be set between +2V/V and +100V/V. Operating from ±5V supplies, the gain control voltage for the VCA822 adjusts the gain linearly in V/V as the control voltage varies from +1V to 1V. For example, set for a maximum gain of +10V/V, the VCA822 provides 10V/V, at +1V input, to 0.1V/V at 1V input of gain control range. The VCA822 offers excellent gain linearity. For a 20dB maximum gain, and a gain-control input voltage varying between 0V and 1V, the gain does not deviate by more than ±0.3dB (maximum at +25°C).