Research On Low Power Comparator

Comparator is one of the most important units widely used in electronic systems. The design of a comparator is based on loop gain amplifier. Comparator is a kind of a nonlinear analog circuit, and there is no linear relationship between its input and output. Compared with amplifiers, comparators are not that widely used, but it is really necessary. The fact is, voltage detectors, voltage level transformer, voltage-frequency transformer, sampling/track and hold circuit, zero detectors, peak and delay line detectors all utilize comparators. Also comparators are fit for system-level applications, such as portable and battery-driven system, scanner, set-top-box and high-speed differential line receivers. Comparators can also be used in clock signal and high-speed pulse recovery.The comparator is designed for 200MHz 8-bit pipelined ADC (Analog to Digital Converter) under TSMC 180nm DP6M CMOS technology. The ADC has high speed, high resolution and low power consumption. Supply voltage is 1.8V, common input mode voltage is 0.9V, the SNR is 45dB at the frequency of 100 MHz input, valid resolution is more than 7.2 bits, INR and DNR is less than 1.2 LSB and 0.7 LSB, the dynamic input range is -300mV～300mV, the whole power consumption is less than 175mW. Transmission delay of the comparator is less than 0.1ns, offset voltage is 0.1 V, power dissipation is 0.37mW. The ADC including the comparator part has been taped out and the chip is under testing.