A 1-V operational sigma-delta modulator with a second-order passive switched capacitor filter is designed and fabricated by using a 90 nm CMOS process. No gate-voltage bootstrapped scheme is adopted to drive analog switches, and the voltage gain of a comparator is chosen to be 94 dB. The experimental results show that the peak SNR reached 68.9 dB with a frequency bandwidth of 40 kHz when the clock was 40 MHz.

Well-crystallized Ba2SiO4:Eu2+ powders were grown on a substrate by the vapor phase reaction between a mixed powder (barium carbonate and europium oxide) and SiO gas. The vaporization of SiO occurs at 1400–1600 from the SiO2 source (or SiO powder) in a reducing atmosphere. The formed SiO gas was transported by 95 vol% Ar - 5 vol% H2 gas and reacted with the raw material powders. The emission intensity of the Ba2SiO4:Eu2 + phosphor synthesized by the new vapor phase technique is about 2.6 times higher than that of a conventional solid-state reaction sample.