Amplifier with temperature dependent gain and temperature compensated bandwidth

A circuit, comprising:

• an amplifier circuit having a gain setting network formed by an input resistor and a feedback resistor;
• wherein said amplifier circuit includes a differential input circuit that is tail biased by a bias current;
• and
• a bias current generator circuit comprising:
• a proportional to absolute temperature (PTAT) current generator coupled in series with a first resistor to generate a reference voltage;
• wherein the first resistor has a temperature dependent resistance substantially equal to a sum of temperature dependent resistances of the input and feedback resistors;
• a voltage-to-current converter circuit configured to convert the reference voltage to a reference current applied across a second resistor;
• wherein the second resistor has a temperature dependent resistance substantially equal to the temperature dependent resistance of the input resistor;
• and
• a mirroring circuit configured to mirror the reference current to generate said bias current.

A circuit, comprising:

• an operational amplifier (OPAMP) with a gain setting network formed by an input resistor with a first resistance R1 and a feedback resistor with a second resistance R2;
• wherein said OPAMP has a bandwidth set as a function of a transconductance of an input stage of said OPAMP multiplied by a first factor equal to
• R
• ⁢
• 1
• R
• ⁢
• 1
• +
• R
• ⁢
• 2
• as set by said gain setting network;
• wherein the transconductance is dependent on a tail current configured to bias the input stage of said OPAMP;
• and
• a bias current generator circuit configured to generate said tail current as a function of a second factor substantially equal to
• R
• ⁢
• 1
• +
• R
• ⁢
• 2
• R
• ⁢
• 1
• .