Pole-splitting and feedforward capacitors in common mode feedback of fully differential amplifier

An amplifier circuit, comprising:

• a differential amplifier comprising:
• a first pole-splitting capacitor connected between a common mode feedback input of the differential amplifier and a first output of the differential amplifier;
• and
• a second pole-splitting capacitor connected between the common mode feedback input and a second output of the differential amplifier;
• and
• a common mode feedback amplifier comprising an output connected to the common mode feedback input,
• wherein the differential amplifier comprises:
• a first cascode;
• a second cascode;
• and
• a load network,
• the first cascode comprising:
• a first transistor connected in a common-source configuration, the first transistor having a gate connected to a first signal input of the differential amplifier;
• and
• a second transistor connected in a common-gate configuration, the second transistor having a source connected to a drain of the first transistor of the first cascode and a drain connected to the first output of the differential amplifier;
• the second cascode comprising:
• a first transistor connected in a common-source configuration, the first transistor having a gate connected to a second signal input of the differential amplifier;
• and
• a second transistor connected in a common-gate configuration, the second transistor having a source connected to a drain of the first transistor of the second cascode and a drain connected to the second output of the differential amplifier;
• and
• the load network comprising the common mode feedback input and being connected to:
• the drain of the second transistor of the first cascode and
• the drain of the second transistor of the second cascode.

An amplifier circuit, comprising:

• a differential amplifier comprising a common mode feedback input;
• a second amplifier comprising:
• a first input connected to a first output of the differential amplifier;
• a second input connected to a second output of the differential amplifier;
• a first output connected to a first output of the amplifier circuit;
• and
• a second output connected to a second output of the amplifier circuit;
• a common mode feedback amplifier comprising an output connected to the common mode feedback input;
• a first feedforward capacitor connected between the output of the common mode feedback amplifier and the first output of the amplifier circuit;
• a second feedforward capacitor connected between the output of the common mode feedback amplifier and the second output of the amplifier circuit;
• and
• a first pole-splitting capacitor connected between the common mode feedback input and the first output of the differential amplifier,
• wherein the second amplifier is a differential source follower.