A Wideband Current Amplifier with DC-offset Cancellation Utilizing Chopper Modulation

A wideband current amplifier with DC-offset cancellation utilizing chopper modulation is proposed. Combining series–series feedback with backgate driven choppers, a wideband current amplifier with DC-offset cancellation is realized. As consumed a power of 1.495 mW under a supply voltage of 1.8 V, measured bandwidth of the current amplifier is 120 MHz, which leads the current amplifier can be adopted to compose the analog baseband of a wideband direct-conversion receiver with bandwidth of 240 MHz (twice of the baseband bandwidth). Measured current gain of the current amplifier is 15 dB. Measured output DC-offset without and with DC-offset cancellation are − 70.8 dBV and − 91 dBV, respectively. Thus, DC-offset reduction of 20 dB is achieved.