An op-amp sharing technique for continuous-time ΔΣ modulators

This paper presents a new operational amplifier sharing technique for a continuous-time ΔΣ analog-to-digital converter (ADC). This technique saves power consumption by reducing the number of active elements in the modulator. Furthermore, the shared amplifier acts both as an adder and integrator in two different clock phases. The proposed technique also can be realized in a noise-coupled delta-sigma ADC. To verify the idea, a 2^nd-order continuous-time ΔΣ modulator has been designed and simulated successfully with and without noise-coupling techniques.