Split miller compensation in two-stage differential amplifiers

A differential amplifier, comprising:

• a first amplifier stage, comprising:
• a current source;
• a first input transistor having a conduction path coupled to the current source, and having a control terminal coupled to a first differential input;
• a first bias transistor having a conduction path connected to the conduction path of the first input transistor at a first intermediate output, and having a control terminal;
• a second input transistor having a conduction path coupled to the current source, and having a control terminal coupled to a second differential input;
• and
• a second bias transistor having a conduction path connected to the conduction path of the second input transistor at a second intermediate output, and having a control terminal coupled to the control terminal of the first bias transistor;
• and
• a second amplifier stage, comprising:
• a third bias transistor having a conduction path coupled to a power supply voltage, and having a control terminal;
• a third amplifier transistor having a conduction path connected in series with the conduction path of the third bias transistor at a first amplifier output, and having a control terminal coupled to the first intermediate output;
• a first compensation capacitor coupled between the first amplifier output and the first intermediate output;
• a fourth bias transistor having a conduction path coupled to the power supply voltage, and having a control terminal coupled to the control terminal of the third bias transistor;
• and
• a fourth amplifier transistor having a conduction path connected in series with the conduction path of the fourth bias transistor at a second amplifier output, and having a control terminal coupled to the second intermediate output;
• a second compensation capacitor coupled between the second amplifier output and the second intermediate output;
• a first cross-coupled capacitor coupled between the first amplifier output and the second intermediate output;
• and
• a second cross-coupled capacitor coupled between the second amplifier output and the first intermediate output;
• wherein the first cross-coupled capacitor has a capacitance smaller than a capacitance of the first compensation capacitor;
• and
• wherein the second cross-coupled capacitor has a capacitance smaller than a capacitance of the second compensation capacitor.

An instrumentation amplifier, comprising:

• a first differential amplifier, comprising:
• a first input stage configured to produce a voltage at a first intermediate output corresponding to a differential voltage across a first input and a second input;
• a first amplifier having an input coupled to the first intermediate output, and an output coupled to a first amplifier output;
• a first compensation capacitor coupled between the first amplifier output and the first intermediate output;
• a first terminal of the first differential amplifier connected to the first intermediate output;
• and
• a first cross-coupled capacitor coupled between the first amplifier output and a second terminal of the first differential amplifier;
• and
• a second differential amplifier, comprising:
• a second input stage configured to produce a voltage at a second intermediate output corresponding to a differential voltage across a third input and a fourth input;
• a second amplifier having an input coupled to the second intermediate output, and an output coupled to a second amplifier output;
• a second compensation capacitor coupled between the second amplifier output and the second intermediate output;
• a first terminal of the second differential amplifier coupled to the second intermediate output;
• and
• a second cross-coupled capacitor coupled between the second amplifier output and a second terminal of the second differential amplifier;
• wherein the first terminal of the first differential amplifier is coupled to the second terminal of the second differential amplifier;
• and wherein the first terminal of the second differential amplifier is coupled to the second terminal of the first differential amplifier.