A 10-bit pipeline ADC using 40-dB opamps and calibrated customized references

A 10-bit pipeline A/D converter using low gain (les40 dB) operational amplifiers (opamps) is presented. Without interfering the normal analog-to-digital conversion, a continuous reference refreshing technique is exploited. This technique effectively reduces the gain requirement of opamp while the conversion speed is not compromised, allowing the use of simple cascode CMOS inverters. The compensation of finite gain of the opamp is made by using customized reference voltages that is calibrated periodically. The technique has been confirmed by intensive simulations. As a result of the relaxed opamp gain requirement, significant reduction in power consumption can be achieved.