A low power third order delta-sigma modulator for digital audio applications

A low-power delta-sigma modulator for digital-audio is presented, which employs tri-level quantization to achieve 97 dB dynamic range, over a 25 KHz bandwidth. The modulator has third-order single loop CIFB architecture as cascade of integrators with feedback and feed-forward paths. A new operational amplifier is designed which is at least 2-times more power efficient than a regular folded-cascode amplifier. A new latched comparator with merged pre-amplification and regenerative paths is designed for the tri-level quantizer, which has very low power consumption as well as high speed and sensitivity. The modulator is implemented in a standard 0.6 mum CMOS process. Its supply voltage ranges in 3.0-3.5 V and its power consumption is 1.5 mw from a 3.0 V supply