Affiliation:
1. ENIS, University of Sfax, Tunisia
Abstract
This chapter presents an ultra-low-power discrete time (DT) second order feedforward (FF) delta sigma (ΔΣ) modulator using an optimizer bulk-driven operational transconductance amplifier (OTA). The designed modulator was suitable for non-implantable biomedical devices in the 2.4GHz ISM band for IEEE 802.15.1/Bluetooth standard. The used OTA was optimized using the PSO algorithm for designing a 2nd order FF ΔΣ modulator. Using TSMC 0.18µm CMOS process, the designed OTA achieves a 40.1dB of DC gain and a 380MHz of GBW while consuming only 10µW under ±0.5V. The modulator has been implemented with an OSR of 50, a signal bandwidth of 0.5MHz, and a sampling frequency of 50MHz with an input signal magnitude of -6.37dBFS. It attains a peak SNR of 55.63dB and a resolution of 8.94bits with a total power consumption of 20µW under ±0.5V supply voltage.