A 3 V 22 mW multi-bit current-mode /spl Sigma//spl Delta/ DAC with 100 dB dynamic range

This DAC chip is a dual-channel low-voltage low-power D/A conversion system associated with filter functions of digital input and analog output. The chip is intended for multi-media equipment that requires multi attenuation control of CD-ROM and multi-system clock frequency for Set-Top-Box. The ratio of analog area to digital area in a mixed-mode chip has been inversely proportional to process design-rules for a given dynamic range objective, which contradicts the LSI trend. This design realizes a high degree of size reduction commensurate with process design rules for the analog circuitry and a signal processing architecture for the digital circuitry. The conversion techniques give -90 dB full-scale THD+N and 100 dB dynamic range with 22 mW power consumption from a 3 V supply. The clock frequency for the system can be automatically switched for applications between 384 fs (CD) and 256 fs (ST-Box) by LR-clock. The chip is fabricated in 0.6 /spl mu/m DPDM double-poly double-metal CMOS.