Variable gain amplifiers with fine attenuation step control and flat signal-to-noise ratio versus attenuation

A method of variable gain amplification, the method comprising:

• receiving a radio frequency (RF) input signal at an input of a variable gain amplifier (VGA);
• amplifying the RF input signal using a plurality of amplification cells of a segmented amplification circuit of the VGA to generate a plurality of amplified RF signals at a plurality of outputs of the segmented amplification circuit;
• selecting one or more taps from a plurality of taps of an impedance ladder of the VGA;
• and
• routing the plurality of amplified RF signals from the plurality of outputs of the segmented amplification circuit to the one or more selected taps of the impedance ladder using a plurality of switches of the VGA, the plurality of switches connected between the plurality of outputs of the segmented amplification circuit and the plurality of taps of the impedance ladder.

A transmitter comprising:

• a radio frequency (RF) digital-to-analog converter (DAC) configured to convert a digital input signal into an RF input signal;
• and
• a variable gain amplifier (VGA) comprising:
• an input configured to receive the RF input signal;
• a segmented amplification circuit including a plurality of amplification cells configured to amplify the RF input signal to generate a plurality of amplified RF signals at a plurality of outputs;
• an impedance ladder including a plurality of taps each connected to a different node of the impedance ladder;
• and
• a plurality of switches connected between the plurality of outputs of the segmented amplification circuit and the plurality of taps of the impedance ladder, the plurality of switches configured to control routing of the plurality of amplified RF signals from the plurality of outputs of the segmented amplification circuit to one or more taps selected from the plurality of taps of the impedance ladder.