A 4th-order 40MHz Bandwidth 12bit continuous-time delta-sigma modulator is presented in this paper. A shaped SC DAC with reduced peak current is proposed to relax the OTA slewing requirement, consuming no extra hardware or power. The DAC static and dynamic mismatches are eliminated by lookup table based digital calibration. With 1.2V supply and 69.6mW power in 90nm CMOS, the modulator achieves excellent SFDR of 84.2dB and 72.9dB peak SNDR at 960MHz clock frequency, corresponding to a FoM of 0.24pJ/Step. The core circuit area is about 0.28mm2.