PURPOSE: To reduce the circuit scale and to decrease the chip size by forming an SC circuit in which a D/A converter(DAC) and a switched capacitor (SCF) are integrated.

CONSTITUTION: Input capacitors of an SC circuit 1 employs plural capacitors 5-7 whose capacitance is weighted in a way of 2m-1 (m is a positive integer, that is, m=1,2,..., n) and a connection control circuit 2 controls their connection or nonconnection to form the SC circuit 1 in which a DAC and an SCF are integrated. The circuit for the modulator is simplified by using an operational amplifier 23 used for an integration circuit in common and implementing the switch control by one connection control circuit 2. Thus, the circuit scale is reduced and the chip size is decreased.