This paper describes an A/D converter for signal processing applications which has a floating point format. This converter has been implemented using CMOS switches, an operational amplifier, a comparator, a binary weighted capacitor-array, and D/A converter for calibration. A 13-bit accuracy has been achieved with the self-calibration technique although the capacitor-array used has a 9-bit accuracy. Also other errors like stray capacitances, charge injection of the CMOS switches etc. are compensated by calibration circuit.