programmable gain amplifier (PGA)
Programmable Gain Amplifiers(PGA) are amplifiers with programmable gain. They are operational amplifiers( OpAmp) in which the gain-determining resistor in the feedback between output and input is replaced by a controllable component.
In the programmable gain amplifier, the feedback resistor is replaced by a D/A converter( DAC) whose level values can be controlled. This, in combination with the input resistor, forms the gain-determining resistor network. The feedback resistor (R(DAC)) simulated by the DAC converter determines the relation between output and input voltage in relation to the input resistance. VAoff/VEin corresponds to R(DAC)/REin.
Since the feedback resistor (R(DAC)) can be programmed in steps with a resolution of up to '2^12', depending on the D/A converter concept, even the gain can be programmed in the smallest steps with the highest accuracy.