A Low-Power Second-Order Sigma-Delta Modulator in 65nm CMOS

Low power high precision second-order feed forward ?? modulator with asynchronous 4-bit successive approximation quantizer is presented. A high-swing telescopic operational amplifier is used in integrator to cover signal swing under low voltage. Asynchronous 4-bit successive approximation quantizer can decrease power dissipation dramatically. The modulator, simulated at the transistor level using 65-nm CMOS technology, obtains a peak SNDR of 90 dB over an input signal bandwidth of 5 kHz.