A new low power 2-2 cascaded sigma-delta modulator with the reduced number of op-amps for GSM transceiver applications

A new single-bit cascaded 2-2 /spl Sigma///spl Delta/ (Sigma-Delta) modulator with only two op-amps, instead of four ones in conventional modulators, to decrease the static power consumption and area, is designed for GSM transceiver applications. The circuit consists of two new single op-amp, second-order, and low-pass loop filters to achieve a fourth-order quantization noise shaping. The modulator shows 84dB DR (Dynamic Range) for GSM signal bandwidth, while consuming 2.3mW from a 2.5V supply voltage.