A 18 mW CT ΔΣ modulator with 25 MHz bandwidth for next generation wireless applications

The design of a wideband low-power continuous-time (CT) delta-sigma modulator is presented in this paper. A modified feed-forward architecture is proposed to realize the low-power loop filter as well as cancel the out-of-band peaking in the signal transfer function. Several high-speed low-power design techniques are used in the circuits. The modulator achieves 60 dB dynamic range (DR) within 20 MHz signal bandwidth, and 55 dB DR within 25 MHz signal bandwidth. Clocked at 400 MHz, the modulator consumes only 10 mA current from a 1.8 V supply.