A CMOS Operational Amplifier with Constant 68° phase margin over its whole range of noise-power trade-off programmability.

The problem of variable phase margin of our programmable Operational Amplifier (OpAmp), which was presented at ESSCIRC 2006, has been solved. The OpAmp is programmable concerning noise and power consumption, while the phase margin is kept at an approximately constant value of 68° for the whole range of programmability. Experimental results for a 0.35 μ μ μ μm CMOS OpAmp show either low noise of 3.6 nV/√ √ √ √Hz or low power consumption of 59 μ μ μ μW, and a phase margin variation of only Δ Δ Δ Δφ φ φ φres = 6°.