I. Introduction
As THE number of wireless communication standards increase, multimode multiband (MMMB) receivers that can cover multiple standards is garnering much attention. It is, however, difficult for a conventional analog receiver to achieve such versatility, since analog baseband circuits such as variable-gain amplifiers (VGAs) and low-pass filters (LPFs) are not easily programmable. In order to cope with this problem, a discrete-time MMMB receiver has been proposed in [1], where LPFs and VGAs are implemented using switches and capacitors. While such an architecture avoids the use of sophisticated analog circuits, thereby enabling higher programmability, the receiver itself is still based on analog signal processing and hence is vulnerable to device mismatch and PVT variations (see Fig. 1).