Low noise amplifier having sequentially interpolated gain stages

An amplifier comprising:

• an input terminal for receiving an input signal;
• a plurality of gain stages coupled to the input terminal for generating a plurality of output signals responsive to the input signal, wherein the gain stages have different noise and different input signal ranges;
• a loading network coupled to the plurality of gain stages for loading the output signals;
• and
• an interpolator coupled to the plurality of gain stages;
• wherein:
• each gain stage has an output;
• and
• the loading network comprises a string of resistors, wherein each resistor is coupled between the outputs of two gain stages.

An amplifier comprising:

• an input terminal for receiving an input signal;
• a plurality of gain stages coupled to the input terminal for generating a plurality of output signals responsive to the input signal, wherein the gain stages have different noise and different input signal ranges;
• a loading network coupled to the plurality of gain stages for loading the output signals;
• an interpolator coupled to the plurality of gain stages;
• and
• a feedback network coupled between the output of the buffer amplifier and the plurality of gain stages;
• wherein the buffer amplifier has a selectable gain.

An amplifier comprising:

• an input terminal for receiving an input signal;
• a plurality of gain stages coupled to the input terminal for generating a plurality of output signals responsive to the input signal, wherein the gain stages have different noise and different input signal ranges;
• a loading network coupled to the plurality of gain stages for loading the output signals;
• an interpolator coupled to the plurality of gain stages;
• and
• a feedback network coupled between the output of the buffer amplifier and the plurality of gain stages;
• wherein the feedback network is a variable impedance circuit.

An amplifier comprising:

• an input terminal for receiving an input signal;
• a plurality of gain stages coupled to the input terminal for generating a plurality of output signals responsive to the input signal, wherein the gain stages have different noise and different input signal ranges;
• a loading network coupled to the plurality of gain stages for loading the output signals;
• and
• an interpolator coupled to the plurality of gain stages;
• wherein the gain stages and loading network are constructed such that the overall gain of the gain stages combined with the loading network is substantially constant regardless of which gain stage or stages are enabled.

An amplifier comprising:

• an input terminal for receiving an input signal;
• a plurality of gain stages coupled to the input terminal for generating a plurality of output signals responsive to the input signal, wherein the gain stages have different noise and different input signal ranges;
• a loading network coupled to the plurality of gain stages for loading the output signals;
• an interpolator coupled to the plurality of gain stages;
• a feedback network coupled between the output of the buffer amplifier and the plurality of gain stages;
• and
• a second buffer amplifier having an input and an output, wherein the input of the second buffer amplifier is coupled to the loading network.

A method for amplifying an input signal comprising:

• generating a plurality of output signals responsive to the input signal using a plurality of gain stages, wherein the gain stages have different noise and different input signal ranges;
• loading the output signals with a loading network that presents different loads to the gain stages, thereby generating a single intermediate signal;
• and
• selectively enabling and disabling the gain stages.

A method for amplifying an input signal comprising:

• generating a plurality of output signals responsive to the input signal using a plurality of gain stages, wherein the gain stages have different noise and different input signal ranges;
• loading the output signals, thereby generating an intermediate signal;
• and
• selectively enabling and disabling the gain stages;
• wherein loading the output signals comprises loading the output signals with binarily weighted loads.

A method for amplifying an input signal comprising:

• generating a plurality of output signals responsive to the input signal using a plurality of gain stages, wherein the gain stages have different noise and different input signal ranges;
• loading the output signals, thereby generating an intermediate signal;
• and
• selectively enabling and disabling the gain stages;
• wherein loading the output signals comprises loading the output signals such that the gain of the intermediate signal with respect to the input signal is substantially constant regardless of which gain stage or stages are enabled.

An amplifier comprising:

• a plurality of gain means for generating a plurality of output signals responsive to an input signal, wherein the plurality of gain means have different noise and different input signal ranges;
• loading means for providing different impedances to the gain means and generating a single intermediate signal responsive to the output signals;
• and
• means for selectively enabling and disabling the plurality of gain means.

An amplifier comprising:

• a plurality of gain means for generating a plurality of output signals responsive to an input signal, wherein the plurality of gain means have different noise and different input signal ranges;
• loading means for providing different impedances to the output signals;
• means for selectively enabling and disabling the plurality of gain means;
• and
• buffer means for buffering an intermediate signal generated by the loading means.

An to amplifier comprising:

• a plurality of gain means for generating a plurality of output signals responsive to an input signal, wherein the plurality of gain means have different noise and different input signal ranges;
• loading means for providing different impedances to the output signals;
• means for selectively enabling and disabling the plurality of gain means;
• and
• attenuation means for generating a plurality of attenuated signals responsive to the input signal, and wherein each gain means receives one of the attenuated signals.

An amplifier comprising:

• a plurality of gain means for generating a plurality of output signals responsive to an input signal, wherein the plurality of gain means have different noise and different input signal ranges;
• loading means for providing different impedances to the output signals;
• means for selectively enabling and disabling the plurality of gain means;
• and means for generating a variable gain output signal responsive to the plurality of output signals.