A 0.39mA 92dB modified-feedback ΣΔ modulator for digital RF hearing aid with 1.2V supply voltage in 0.35µm CMOS

A 0.39 mA 92 dB dynamic range switch-capacitor (SC) third-order ΣΔ modulator for a digital RF hearing aid in 0.35 μm CMOS is presented here. A modified-feedback topology is used here that effectively achieves a high dynamic range and the low power consumption. In the implementation, the bootstrapping-switch and the low-voltage wide-swing OTA are essentially designed for 1.2 V supply voltage with the 0.35 um CMOS process. In the measurement result, this modulator achieves 90 dB SNR in a 10-KHz bandwidth with an oversampling ratio of 128, and its power consumption is 0.47 mW with a good FOM of 555e-6.