Switched-Capacitor Analog Correlator using Balanced Charge Pump Circuit for CDMA Bus Interface

A switched-capacitor analog correlator using balanced charge pump circuit, capable of pumping same amount of charge in positive and negative direction is proposed for code division multiple access (CDMA) bus interface. In addition, the amount of charge injection is independent of the output voltage. The above properties are desirable in CDMA bus interface because failing to do so would result in the bus saturated to one end. We have analyzed the effects of process variation and parasitic capacitance of the proposed circuit. The new circuit operates at 100 Mhz. Simulation results by using 3.3 V supply voltage, verified that the new circuit fulfilled its design needs.