Design of analog circuits in multi-bit quantized audio DAC
HAN Yan1, LIAO Lu1, HUANG Xiao-wei2, ZHANG Hao1, WANG Hao1
1. Department of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, China; 2. Institute of Microelectronic CAD, Hangzhou Dianzi University, Hangzhou 310018, China
An analog circuit with high resolution and low power in a sigma-delta （Σ-Δ） digital-to-analog converter (DAC) was designed . By adopting 4-bit quantized technique，this DAC not only enhances the stability of the modulator, reduces the power consumption and the occupied area, but also reduces the system requirements for the back-end low-pass filter. Realizing methods of different modules were given, besides, design techniques in crucial modules that generated nonlinearity, such as switched-capacitors and bandgap reference, were discussed . This design was fabricated in SMIC 0.18 μm mixedsignal CMOS process and verified. The measured results showed that the chip had a peak SNDR of 89 dB and a 96 dB dynamic range (DR), and consumed a total power of 19.1 mW, and this value droped to 9.1 mW without buffers. Moreover, the prototype yield was 90%, achieving high precision and low power dissipation.
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