| Popis: |
In this paper, we present a single-chip delta-sigma DAC and a class-D amplifier that utilizes internal antialias low-pass filters (LPF). The clock frequency of the delta-sigma modulator is lower than that of the delta-sigma DAC in order to reduce the power loss. The use of a closed-loop class-D amplifier with a balanced structure synchronized by a common-mode clock signal can drastically reduce aliasing noise and increase the LPF cutoff frequency. The chip area of the antialias LPF is reduced by one-hundredth. The test chip is fabricated by 0.35-/spl mu/m CMOS technology. The measured SNR, dynamic range, and THD of the test chip for audio applications are 94.7 dB, 95.0 dB, and 0.19 dB, respectively. |
