A Very High Slew-Rate Dynamic CMOS Operational Amplifier

We present a dynamic CMOS operational amplifier with a special input circuit which injects an extra bias current to increase the slew-rate, depending on the input signal. The performance of this operational amplifier is compared to a conventional operational amplifier when used in a sample&hold circuit. The maximum operating clock frequency of the sample&hold circuit increases from 290 kHz up to 1 MHz with a hold-capacitor of 1 nF. The amplifier has been fabricated in a 5 ¿m CMOS process and dissipates a static power of 7.5 mW.